I'm not sure how applicable to criterion is to investing. The main differences are you typically don't lose your entire 'bet', and bets aren't decided in a single moment but the outcome is slowly revealed over time.
I don't think that changes the conclusion, you're just moving from discrete to in theory continuous but in practise modellable as discrete.
It prompts very different behavior, to extend the coin flip metaphor: If you could slow down time and see the flip turning bad, you could quickly withdraw your bet. Then you'd be much more likely to bet a higher fraction.
I was thinking about this while reading. The Dot Com and Sub Prime mortgage crashes took a lot of people buy surprise, but not everyone. Moving into T-bills, cash, or precious metals at the beginning of those downturns would be enough to make the 2x Kelly and 3x Kelly perform better.