Riddle me this: Google Drive is trying to back up my WhatsApp?

I was getting some notices on my Android that a backup was failing.
So I double tapped it after several of these and discovered it was
Google Drive trying to back up my encrypted WhatsApp. And telling me I needed to do
something to do that backup.

I delete my WhatsApp convos almost daily for the reasons one uses WhatsApp.
Why would I want to back them up to Google Drive?
Why would Google Drive be attempting that automatically?
I don't remember enabling something like that.

I thought Google Drive was Google World and WhatsApp was Microsoft World.
Seems like that should be the twain that never meets.
Any thoughts?