I had the same initial response, but I think what parent us saying is that people should consider using this engine, rather than spinning their own?

I'm not sure I agree, as many great games are built on in-house, bespoke engines, or else custom modifications to existing engines. But for the purpose of rapid prototyping, the intended use of this engine, it definitely makes sense to use a preexisting engine in most cases.

I could be wrong about parent's intending meaning though.