Gregory's ServerI think a key component of Google's "Backup and Sync" is that the meaning of the words are different than you expect.
It backs up thumb drives and syncs Google Drive folders, sort of. (But not in a way that makes sure Important-Folder has the same content downloaded on both systems. It may just be a reference to that content.)
Technically, it does "backup and sync" but just not in the way most people really want.