When choosing between two options, it is better to go with the one that has the higher probability of success. Considering BYU scored on 6 of their 21 possessions (including both OTs) the probability of scoring might have been as high as 28%.
I am not saying that they shouldn't have been giving effort to block the kick, but giving a TO to that effort was bad game/clock management. is there not a play card that says "all-out FG block" where you could relay that in without the timeout?