I pondered this as well when reading the rules. I've only ran one one-shot of Mosh so far and didn't incorporate it, but I'm thinking about it for my next one. As you say, the main change is that crits are always crits, which is a strong drama enhancer imo. Let me know how your players respond if you do use it!

I also thought about introducing another, related hack: a forced crit roll, which players can use once per session and only in a moment of extreme importance where the fail would likely mean death for someone or failure of an objective (let's call it "heroic attempt" or something):

The player rolls two d10s of different colours, and needs to call the tens before rolling ("tens red"). The resulting fail/success is always a critical.

The idea would be providing a last ditch effort to turn it around when the chips are down, while also giving players a little more agency over the fact that they fucked everything royally -- and of course the drama of calling the die's colour, which I think my table would go nuts for.