String theory often gets ragged on for not having any direct practical applications, which is certainly true. However, some of the mathematics developed by string theory is key in theoretical work in fields where theory and experiment have a much tighter bond. For example, topological quantum field theory[1] has found widespread important applications in quantum information, and it was pioneered by none other than Witten himself. This isn't just on the theory side; experimentalists are looking at topological states of matter for a variety of applications, including quantum computing.

[1]: https://en.wikipedia.org/wiki/Topological_quantum_field_theo...