I use that here... The fact that it is needed at all is already a failure of the OS.

And the Desktop app itself is sort of unstable, and classic shell is also sort of unstable, the combination result in lots of crashes, specially if you are having issues while trying to play some games (example: on my machine every time I scroll the map too much in Arcanum from Troika Games, it crashes, crashes the desktop, crashes the classic shell, and the mouse stops working completely... it is really amazing, it crashes so hard I am impressed instead of frustated).

The fact that one has to install Classic shell even on Windows server versions speaks for itself.