... ridiculous, unlucky, close losses to Utah during that loss streak that when that play happened where he was called out of bounds, there was a very real risk that Utah gets a defensive stop and the ball back with 5 minutes left, only down 6 points. Say what we will with perfect hindsight, but we all felt there was a very real possibility of a 1 point loss for BYU (quickly noodling through that scenario just laid out) at that moment. Now, I will agree with you from the point a few game minutes later with BYU driving into easy FG range (even before kicking the FG) where it was clear BYU should get at least 3 points, that it was better with them being able to burn more time off the clock and secure a 2 score lead.
Otherwise, using your logic (and I am not picking on you here at all, so please do not take it that way), it absolutely would have been better to get the Hall TD if having to make a decision in the moment when he was ruled out. If the assumption is BYU could have ball hogged time off the clock, then going up 12 or 14 points with half the 4th quarter left would have been obviously better (in that moment). Even if Utah scores a TD in, say, 2 game minutes, BYU could then resume their ball control offensive time drain and run out time. If the ultimate assumption is that, at the moment Hall was called out, BYU could run it and drain the clock, then it is better to go up 12-14 points. The only concern would be a very low percentage onside kick after a TD by Utah, or a turnover by BYU (which could have happened anyway after Hall was ruled out, though thankfully it did not).