It may seem that way, but using a high winning chance gives only a slight advantage for accumulating tokens. Only when you play with all your STEEM tokens, it will matter. You will only have less risk short term.
For Magic Dice only long term matters. Thus every bet is equal.
It doesn't matter if you bet with 50% or 94%. All those bets have the same house edge of 2%.
Yes, I've been through a learning process on this in the last day or so. It makes a lot more sense to me now, interesting system.