Developing relatively large systems with dozens of different, mostly JVM-based services.

Easy interplay between linux and windows programs on the same files.

WSL2 in particular lets me use a BTRFS partition and expose it to windows with a lot less awkwardness than the VM I had before.

I develop web apps on Windows but since I want to run them under Linux, WSL is handier for testing than using a virtual machine or a Linux box.

Having a fully/proper/native Linux shell that is always just one wsl command away.

Web development primarily

Web development with node and ruby it seems.

Java and .NET Web development has been perfectly fine the last decades.

Node, PHP, anything Docker all seem to work better under WSL2 than windows itself.

Node and PHP has been running in Windows just fine for years everytime I have to deal with them.

Also node is not going to stop downloading the whole Internet regardless of the host OS.

Or most open source non-windows software work. So many tools run great (or only run) under Linux, and dev tooling for these projects is also heavily Linux-centric. Often you might be able to get a package working under Windows, but support is thin and it's prone to breakage. Easier to just run it under Linux in a VM, like what WSL2 is doing.

Development of an application, which runs on Linux.