Anthropomorphically forcing the world to have particular laws of physics by more effectively killing yourself if it doesn't seems... counter-productive to maximizing how much you know about the world. I'm also not sure how you can avoid disproving MWI by simply going to sleep, if you're going to accept that sort of evidence.

(Plus quantum suicide only has to keep you on the border of death. You can still end up as an eternally suffering almost-dying mentally broken husk of a being. In fact, those outcomes are probably far more likely than the ones where twenty guns misfire twenty times in a row.)