Maybe the reason we tend to choose bet 2 over bet 1 (before computing the actual expected winnings) is not the higher probability to win, but the smaller sum we can lose (either we expect to lose or we can lose at worst, I'm not sure about that). So the bias here could be more something along the lines of status quo bias or endownment effect than a need for certainty.

I can only speak for myself, but I do not intuitively value certainty/high probability of winning, while I am biased towards avoiding losses.