I don't think you can equate Kalshi style "prediction market" with gambling in Vegas. The worst thing that can happen in Vegas is you the gambler go bankrupt. In the meantime we already have reports of war intelligence in Ukraine being distorted so someone who betted on frontline movements can pocket some cash. Losing a war because some rich degenerate is trying to bet his way towards a second Ferrari is less unlikely than you imagined.
The reports that were altered were public reports at the ISW from open reporting, not government intelligence. If you lose a war because you based your tactics and strategy off of media reports instead of your own intel, you weren't going to win that war anyway.
That said, I recognize the broader point. Betting on everything, especially things that betters can directly influence is incredibly dangerous.
Someone blew a hair dryer at a weather station at Paris CdG airport to win a bet.