it's a very good question. I haven't really thought about it. but now that you ask, I think it is something in the between.
on teh one hand, you can use it for a final goodbye to someone, but not neccessarily, you can also use it as wishing all the best to your friend as in "I know we do not talk pretty often so I wish u the best" or "It's your birthday, I do wish you all the best". there