Comment by troydavis

Publishers of audio products (soft synths, DAWs), games, and a fair number of domain-specific products have told their customers not to upgrade yet.

Here's a rundown of products that depend on 32-bit support or that haven't been tested in 64-bit on Catalina yet:

Audio products: https://www.sweetwater.com/sweetcare/articles/macos-10-15-ca...

Games: https://www.macgamerhq.com/opinion/32-bit-mac-games/