Seems like a not great call, but I can think of worse. Like not handing the ball off to Marshawn Lynch on second down at the goal line? Thanks Pete!
4th and 5 is not a gimme. But if you have three timeouts, there is logic to going for it on 4th down as the 64 yard field goal is a looooong kick. However, the field goal is providing you with a guaranteed shot at victory, where as 4th and 5 conversion attempt is likely only extending the drive. With 64 yards being a hard kick, I think the right shot is going for it, BUT I don't think kicking a field goal to win is as bad as it sounds.
To put the entire sequence in it’s proper context you have to consider how much time was left (50 seconds after the 3rd down play) and how many timeouts you have left, which was 3. Considering that, and you have a franchise QB on your side, IMO the decision was a no brainer. Obviously like you stated, there are no guarantees on 4th and 5, but my chances for victory are exponentially greater if I go that route. Now if there was time for only one final play, I would say attempt the 64 yard FG vs. a Hail Mary pass.