If you're dealing with picky eaters (many ball pythons), they will rarely take food out of the tank. And I have never had a problem with cage aggression (associating your hands with food) with a ball python. Ever.
On the other hand, incredibly aggressive feeders (my boas) don't care where they are or where they usually eat, if they smell food they're going to go nuts. Good luck trying to pick up a boa that smells food.
The way I see it, feeding in a separate tub makes no sense. Hook training is an easier solution to cage aggression, though with ball pythons it's rarely necessary. But if feeding in a separate tub works for you, whatever.