useless? are you kidding me? i mean come on, have you ever herd of a kill move? cause she only has a few and that's one of them. but thats not its only use. its great on stages like battlefeild and smashville where a plattform is right above you. not to mention for edgegaurding. and yes folks it is very possible to edge guard with utilt and here is how.
(edge guarding for dummies)
distance yourself away from the edge your opponents on by about a marth's fsmash away and start charging your charge shot. naturally, the opponent doesnt want you to fully charge the charge shot making them approach from the ledge most likely with an aerial. you should be far away enough so that they wont just use the ledge attack as an approach yet close enough for the utilt to hit. distance yourself so that they must forfeit their invincibility by jumping towards you to attack as opposed to ledge attack etc. now all you must do is read when they are about to aerial and quickly shield cancel the charge shot and do an utilt. its just that simple. and since the utilt kills easiest while your opponent is in the air, it results in an earlier kill.
the more you know.
Again... edge-guarding for dummies. The only people that will fall for it are dummies who have no experience in the game or have no experience against Samus. After the first use of it, however, then it becomes useless (unless you are up against a dummy. The adage "Fool me twice, shame on me" comes to mind.) It's not even a proper mind game because they will let you charge the charge shot rather than risk being mind gamed.
And, for the sake of the argument, let's say they don't let you charge, they're not going to approach with a sh-aerial because almost everyone knows by now Samus can cancel into shield. They will more than likely approach with a sh-air dodge. By the time u-tilt comes within distance, they'll either air dodge it or land and perfect shield. Punishable. I'm not saying it's not possible to land the kill with u-tilt... but at the same time, I'm not saying it's not possible to land f-smash with Snake on someone who spam spot dodges either. XD
As for using u-tilt below platforms such as BF, sh u-air is definitely more useful. A faster threat to the opponent and easier to follow-up on whether or not they shield. A blocked u-tilt is more punishable than a blocked u-air.
For the sake of u-tilt being one of Samus' kills moves, yes I agree. But, it has even less probability of landing the kill than b-air does. It doesn't kill (until fairly high percentages) when they're grounded and you're not going to hit an opponent in the air as often as they just **** you before it lands.
I'm sorry, but the uses for u-tilt are too limited. If there are two moves that are almost never used by Samus mains, it's between u-smash and u-tilt. Simply because u-smash can 1) be used to read air dodge-recoveries and thus punish, 2) used against big and tall characters (DDD/Snake/DK and even Marth) and more importantly, 3) it comes out several frames faster than u-tilt, u-smash is the more useful of the two.
This is just my opinion of course. Don't take it too seriously if you disagree with any of this.