Maybe I'm too hungry for efficiency but this kind
of redundant
repetition of work strikes me as pointless. What's more, deleting
another's edits and resubmitting them as your own seems plagiaristic -
credit where credit's not due.
The correct person should be credited in the edit summary, that's
true. It does seem pointless, but if you're going to let banned users
edit then they aren't really banned, are they?