The premise of 2) is entirely correct, they just underestimated how irrational people can be.
SBF was a sociopath who would (acdg to sworn testimony of his GF) actually go ahead and toss the coin if the outcome was one side results in the world getting twice as good and the other side causes the world to be destroyed, and he DGAF that he was also making the bet for everyone on the planet.
They didn't count on the fact that this mentality would also mean that in real life, he would also do all kinds of risky crimes, and even go to trial instead of taking a plea deal, because there's a non-zero!! chance he could get away with it.
Bad bets all around
It could be true he's probably a sociopath, but having an edgy philosophical talk with your girlfriend is just that. It could say something about his character but it's nothing more than a fantasy.
Much more damning is stealing all those billions to become rich and famous.
I saw an article that implied that SBF confirmed on the stand his willingness to do the coin-toss, but I couldn't find it to confirm.
Perhaps the biggest evidence is that he went to trial instead of taking a plea deal. At the very least, he put his parents and family through an awful and unnecessary ordeal, just because he thought there was a chance he could convince a jury. But, in reality, it was not even close.
The "pretty sure" caveat is that I cannot offhand recite chapter and verse of all the citations.