There was a time when I used to think the same, then I found my backups were corrupted (or stopped because run out of space, etc) just in the moment when I needed them.
Well, our storage server barfed and the data was gone. Went to restore from backups, all the hourly tar files were there... but were zero bytes.
We looked at the backup script the engineer had put together and it was one of those classic “didn’t give the right parameter to have tar recurse” type bugs. Unfortunately we lost all the photos of the foundation and much of the photos of the electric being run. Oops.
The "normal" use case seems to have a recursive archival. Sounds like somebody chose the wrong default... would be an interesting software archaelogy project to figure out where this "feature" originated.