At least for me, WSL1 had pretty good performance on the Windows file system. On WSL2 accessing the Windows file system is pretty slow.
You can read about it here: https://github.com/microsoft/WSL/issues/4197
You can read about it here: https://github.com/microsoft/WSL/issues/4197
In practice, this turns out to have meant DOS, OS/2, and a barebones POSIX workalike. Modern Linux is too huge and provides useful APIs that go against the grain of modern NT, so applications are slow in WSL1 and there are too many impedance mismatches to paper over to make the investment worth the effort.