There's a lot of assumptions in the comments that Nintendo is behind this. If you don't know much about DraStic, that would be a likely explanation. However, in the specific case of DraStic, that is not the most likely explanation. The more likely is that DraStic is abandonware, and this is Google's very Google-y way of cleaning this up.
The thing to know about DraStic is that it's not an actively maintained app. It had two major developers - one of whom dissappeared a long time ago, to the extent that the remaining developer has not been able to contact the former. The remaining developer is the emulation backend developer, but is by own admission no expert on Android, and the emulation's GUI and system integration. As a result, nothing much has happened to this emulator for years. Although _some_ compatibility fixes with the Play Store have been released a few years ago, DraStic has not been updated to use e.g. Android's Scoped Storage requirements.
What I think we're witnessing here is Google's extremely rough way of cleaning up (what it considers to be) abandonware. It may not even be related to DraStic not using the right Android APIs - it may be as stupid as developer fees not being paid, or some more kafkaesque Google thing.
The entire situation around DraStic is a bit of a shame. DraStic is a very impressive piece of software from a previous age - achieving full speed Nintendo DS emulation on 2010 smartphone hardware. In contrast, other Nintendo DS emulators - most notably MelonDS and DesMuMe - barely achieve full speed on certain DS titles on modern smartphone hardware.
The remaining developer has been promising an open source release of DraStic's emulator code for a long time, but has never delivered. They cited technical milestones to achieve before open sourcing, which are difficult to make if you're burnt out on your software. The biggest shame there is that the open source release would likely propel it to become the most versatile Nintendo DS emulator out there [1], but I'm afraid it's doomed to be a closed source, abandoned and outdated Android app.
Finally, Nintendo has never gone after emulators. In the US, there is only legal precedent that emulators are legal [2]. Nintendo risks cementing the legality of emulation more by trying (and failing) to persecute emulators. Having an abandoned emulator in the Play Store removed while keeping gazillions of other Nintendo systems up there doesn't seem like the way to fight emulation.
[1]: MelonDS is a more accurate emulator and fully open source, but it is much more demanding than DraStic - requiring a PC or recent high end smartphone to run all DS games full speed. DraStic would be efficient enough to allow for enhancements like runahead input lag compensation that cannot as easily be achieved on MelonDS without very fast PC hardware. The remaining DraStic developer is also the developer of gpsp, a Game Boy Advance emulator that is fast enough to run most GBA titles on Sony's old 2004 PlayStation Portable - there's a real reputation of efficiency there.
Based on my own interactions with Google, this seems the most likely.
We have a niche educational/medical app directed to children, to help them understand their treatment with kid-friendly characters talking to them on their level.
The app was taken down because some form had been added to the Google Developer console (the backend of google play) years after we had published and we hadn't answered it. We only found out because someone else in the company heard from a customer that they couldn't find the app online.
A cursory glance showed that the app wasn't listed any more.
After we logged in to Google Developer console, and explored through google's ever changing menus and product renames, we had found an alert to fill out a form. We only had to tick no to a handful of questions on the form and submit it.
The questions were things like: "Is your app a news app?", "Does your app feature sexual content?", etc... All things that google should have been able to figure out based on the rating stuff we had to fill out when the app was first published.
I'm not sure I buy that; the Drastic UI is a bit odd on Android as it uses its own game-style renderer for UI rather than Android UI. But I frequently find apps that give you an actual warning when launching that the app is out of date (in terms of target platform and API level) and you should contact the developer to see if there's an update; and often the permissions API used pops up the "old style" permissions UI where you have to accept all, rather than granular permissions. Those apps haven't been taken down, to my knowledge, and I still come across apps that do this as recently as last week. Drastic doesn't have such a warning, and it uses the modern granular permissions API.
The thing to know about DraStic is that it's not an actively maintained app. It had two major developers - one of whom dissappeared a long time ago, to the extent that the remaining developer has not been able to contact the former. The remaining developer is the emulation backend developer, but is by own admission no expert on Android, and the emulation's GUI and system integration. As a result, nothing much has happened to this emulator for years. Although _some_ compatibility fixes with the Play Store have been released a few years ago, DraStic has not been updated to use e.g. Android's Scoped Storage requirements.
What I think we're witnessing here is Google's extremely rough way of cleaning up (what it considers to be) abandonware. It may not even be related to DraStic not using the right Android APIs - it may be as stupid as developer fees not being paid, or some more kafkaesque Google thing.
The entire situation around DraStic is a bit of a shame. DraStic is a very impressive piece of software from a previous age - achieving full speed Nintendo DS emulation on 2010 smartphone hardware. In contrast, other Nintendo DS emulators - most notably MelonDS and DesMuMe - barely achieve full speed on certain DS titles on modern smartphone hardware.
The remaining developer has been promising an open source release of DraStic's emulator code for a long time, but has never delivered. They cited technical milestones to achieve before open sourcing, which are difficult to make if you're burnt out on your software. The biggest shame there is that the open source release would likely propel it to become the most versatile Nintendo DS emulator out there [1], but I'm afraid it's doomed to be a closed source, abandoned and outdated Android app.
Finally, Nintendo has never gone after emulators. In the US, there is only legal precedent that emulators are legal [2]. Nintendo risks cementing the legality of emulation more by trying (and failing) to persecute emulators. Having an abandoned emulator in the Play Store removed while keeping gazillions of other Nintendo systems up there doesn't seem like the way to fight emulation.
[1]: MelonDS is a more accurate emulator and fully open source, but it is much more demanding than DraStic - requiring a PC or recent high end smartphone to run all DS games full speed. DraStic would be efficient enough to allow for enhancements like runahead input lag compensation that cannot as easily be achieved on MelonDS without very fast PC hardware. The remaining DraStic developer is also the developer of gpsp, a Game Boy Advance emulator that is fast enough to run most GBA titles on Sony's old 2004 PlayStation Portable - there's a real reputation of efficiency there.
[2]: https://en.wikipedia.org/wiki/Sony_Computer_Entertainment,_I....