It's Wine, but with additions made by full-time developers who are paid to work on it, backed by a support team that you can go to and say "Hey, help me get this Win32 app running".

What you get here is Wine and some level of guarantee that what you want to run will run. The focus is on applications rather than games.

Codeweavers contributes back to Wine upstream. Most changes that go into the Crossover fork of Wine end up in the main source tree, so this is a very good way of supporting Wine development and getting something out of it, but if all you're doing is playing games then you're mostly covered by Proton.

When Win10 EOLs I think CrossOver will be very important for allowing organisations to keep MS Office.