Development. At work we rely heavily on it to get work done because having an almost-linux-like environment is much better than having to run a WAMP stack or similar silly stuff.

It's made mine and my coworkers lives so much easier compared to before, so I'm certain use cases exist. Since WSL2 runs on HyperV, for some of my coworkers it's not an option, since they rely on VMware and similar for other essential work.