OT Coin Toss = 49'ers Demise?

Right, but if you have the 2nd possession, there is no guesswork on being conservative or going for it. You know exactly what you need. The game is in front of you.
Yes, that's certainly part of the calculus in the decision, and if I were the head coach, I'd probably want to have the ball last. And to be clear, I'm not arguing that playing for the second possession is the wrong call. I'm just saying it's not that obvious when you consider all of the possible outcomes and I think either way is a valid decision.

Some coaches might want their defense on the field in that crunch situation. And I believe part of it was that SF defense had been on the field for a long drive to end the 4th quarter and needed a rest and that went into the decision as well.