It can be nice to checkout some Git repositories that have this. It can also be nice to catch miscapitalizations of filename imports when those would fail on Linux, etc. One of my past workplaces actually had that problem, they mis-cased imports and the product failed to build on Linux. Nobody caught it because they all used macOS or Windows, I was the first to try WSL (this was before I switched back to Mac)

You would be asking for a world of hurt to put your root filesystem in a case-sensitive volume though. All sorts of software and applications have silently relied on case-insensitivity for decades. You can sometimes fix it on a case-by-case basis, but sometimes you can't, and it's also annoying for it to happen in the first place. Better to have a separate case-sensitive volume just for the stuff you want to be case-sensitive.