“While you have a valid point that the sample size is too small, it is not the case that “still tied” is the same as “lose”.”
It is the same if you are asking whether winning the overtime coin toss significantly increases your chance of winning the game vs not winning it - which is what is being asked in the first calculation.
Of course the ~50% chance of making a field goal might have a big influence on the outcome of a game because it directly affects the score of the game. Neither team can score during the coin toss, so it cannot directly affect the outcome of the game.