Is there any benefit at all to working the same muscle groups

No because without rest they won't repair themselves and you won't make any gains.

Yes. It's something you can do with certain muscles like calves. They react very well to lots of work. The bigger the muscle the more time you probably want to wait between working it. Honestly you can work any muscle every day given that the volume/intensity is pretty low and still have sufficient time to recover. I wouldn't do it for shorter periods of time personally, but find whatever works.

Yes don't fall for the rest meme it's a trick so you fall behind in gains