If we're investors, and not gamblers, why do we get an explanation about negative value bets with only gambling examples? It feels like negative value bets don't exist in investment.

You can't say a bet is negative value when you don't know the odds, and the whole reason people are making so much money market making is that no one actually knows the odds, so no one knows the "real" value of any instrument.

If you're trying to say we should come up with an expected value of the bet before making it, why not give an example on how you'd try that?

The reminder of the Kelly Criterion is great, and I think the article would have been better with a little more practical example of how to apply it. The first half of the article feels like it could be condensed to "Gambling is when you pick bad investments" which is ridiculous..