a focused rationalist should regard all bets with odds far from a coin flip with suspicion; there are often better bets, and with more information for calibration.

Indeed, and this made me wonder if we attach some privileged weight to things explicitly defined as "the lottery" and "sweepstakes." In other words, are they such because they give you a chance at a prize for no money down?

If that's all, then someone who can reliably win at poker or some other set-ruled game could be said to be winning "sweepstakes" all the time were we able to conclude that their skills made it highly improbable that the buy-in would ever be lost (thus equivalent to "no money down", in a sense).