If you feel that being up 11 gives you a greater odds of winning than being up 10 and you also believe that the odds of ASU blocking a kick and scoring on it are WAY smaller than the odds of ASU scoring and getting the onside kick then you would have to conclude that you go for it.

If you disagree with those assumed odds, fine, but you can’t ignore them when trying to pick the best option.

For example, in the next 100 years in CFB you might see 5 times where a team returns a blocked kick in a situation like this. During those same 100 years, you might see 50 times where a team is down 10 with 1:20 left and comes back to win it. If those teams had been up by 11 you would probably only see 25 times that they came back since they would need to get the 2 pt conversion as well.

Since the odds of a blocked FG return are way smaller than all the other outcomes, you go with the outcome that is most likely to win you the game. It is the least risky option as it makes you less susceptible to the other team beating you.