I admit I am out of depth here. What is the difference?
This boils down, as far as I can tell, is the CFTC has preliminarily been told that its authority to exclude these kinds of contracts only apply to “gaming” and not “gambling” (where gaming involves being a participant in a game of stakes). So Kalshi is trying to say that essentially supersedes state laws. I doubt that will hold water in the long run, but you never know until a court rules.
Derivatives exchanges are handled separately from betting because they have other tangible benefits the to financial marketplace. I'm not sure I buy the pitch that prediction markets should fall into the same carveout at face value, but why has nothing to do with how many stats are run.
2016 called
At no point was Hillary Clinton 100% guaranteed to win the election. 538's final call right before the election was 65% Clinton, 35% Trump; or in other words, under Nate Silver's model, Trump had a 35% chance of winning. And he did win, and just barely at that.