It's worth because you spend less effort getting pretty much the same weapon, just with slightly different stat distributions that don't matter as much as the skill itself.
By the way, the menu you're looking for is a 3 line icon hidden away at the bottom left of your screen. Sure, it's not as easily noticeable, but I'd say it's worth getting used to the new UI, some things are actually made a bit more convenient now.
Union events eventually cycle reprint, I don't see a reason you'd keep them on hand given that and their shitty stats and passives...
Other character atk might be worth a sub however.