You overlook the fact that a coin toss is a 50/50 proposition. If you have the chance to go to OT at home, go to OT don’t lose the game on 4th down.
Also, at that point, the Lions had basically gifted 14 of 31 points to Seattle. Lions defense had held Seattle to multiple FG attempts, most of which Seattle failed to convert.
I do agree that we are likely going to regret not taking Carter. Even with Hutchinson they could not get any pressure on Smith.