It transfers the bells to your account the next day. It's a lot easier than having to drop bells everywhere and pick them up and run them to storage (my town doesn't really have any space for bells tbh). It wouldn't be viable for that many bells if re-tail was really far away from the train station because of the time it takes to run to the mail and back, but like I said, my shop is right next to the station so it's the best way, I think. I'm really happy that you're getting him, though. I can tell you're gonna take great care of him.
And it's super nice of you to chip in, Kyoko. You guys are both so nice omg