I'd throw the hail Mary also for some of the same reasons you stated. 57 yards is a lot of pressure on any kicker especially with a game on the line. It will be missed 9 out of 10 times by the best kickers, in a game type situation. With the Hail Mary at least you have the possibility of a defensive penalty extending the game and possibly setting up a much more makable field goal should the play be unsuccessful. I'd say the coach not only made the right decision, but made the decision that 95 % of all coaches would of made.