I see it, but it just looks like it uses internal storage. So far as I know, there's no Drive File Stream/Dropbox sync for Android, so you'd still lose your shit if you weren't manually backing them up somewhere.
I doubt that's a habit many people will develop for a setting they didn't even know existed.
It's not going to help a casual user but I solved the problem by putting the Signal backup in a Syncthing shared folder. It's been a workable solution at least 2 phone swaps now
I doubt that's a habit many people will develop for a setting they didn't even know existed.