When you are 11 points behind with 4 minutes to play, the only way you can win in regulation is by scoring 2 touchdowns....so everyone should be in agreement that we are talking about a situation where OT was the best reasonable scenario, because even if you make the first down, then make a touchdown, and then make a 2-point conversion.....3 uncertain variables.....you are still almost certainly going to be in the situation...if you get the ball back....of trying to get into position for a tying field goal to force overtime. You are very unlikely to score two touchdowns in this amount of time.
A field goal from that position was almost like an extra point....a virtual sure thing....which took no time off the clock. That eliminates all those first three variables and gives you more time to try to reach the same goal...forcing an overtime....that you would have ended up trying to accomplish by going for it on 4th down. You needed three things in either option: a FG, a TD & a 2-point conversion. Clawson chose to get the sure thing for one of them without using any more time off the clock. It was obviously the correct thing to do. If he had gone for it on 4th down and not made it, the game would have been over....and even if he made the first down, he was using up precious time and would have still needed the same three scores.