You're forgetting how cunning the Utes are. They don't REALLY care if he's that good or not (they'll take that risk). The chance to snatch over a legacy kid with a strong BYU pedigree is too good to pass up. They'll do everything they can to make him successful, and turn him into another poster boy of "what Utah can do that BYU can't."
And if he doesn't end up being that great, not a huge loss for them. They made their fans happy about him turning on BYU and they got a Kaufusi on the roster. It's all about recruiting. Smart move for them, honestly.
I don't like the way Devin has gone about this (indirectly down-talking BYU and tweeting out Anakin Skywalker GIF's), but we have a full roster of guys who are putting in work and want to win. Nothing in sports would make me happier than for BYU to smack Utah in the mouth this year. Fingers crossed the season still happens. Go Cougs!