UpB does combo into stuff, you just have to carry people up to platforms with it. It works best on fastfallers, though. Its hard to say what links into what..because theres DI and this is melee, but its terribly easy for opponents to get 'snapped' to platform, miss the tech, and get smashed ftl. (or jab reset to grab)
This last tourney I UpBed a Falco to the top of FoD, and launched him with enough stun to follow up to a quick DJ'F.air.
UpB out of shield is great for when they're behind you. You could potentially bait their shuffle with your back turn, aim your shield, UpB carry them to the platform above. UpB can sometimes be your only follow up option after d.air or upair if you drop ideal positions. Done right, its safe damage.
UpB Canceling is...meh. Theres a couple situations in footsies, wheres its good if you anticipate a grab, but just regular UpB doesn't get enough credit.