The mysterious part would be a joke. The actual reasoning, which Yarvin himself has explained, is to unify the underlying data values between booleans and c-style return codes. In C and unix, the convention is that 0 indicates program success and any other value indicates some kind of program failure. It's strange for the fundamental success code to be false when cast as a boolean, so it makes sense to either change the success codes or change the booleans. Changing the success codes would actually be pretty incoherent - what would you do, 0 and >1 values are failure and 1 is success? - so it makes more sense to change the booleans if something is going to change

Not saying I agree it's worth the trouble. Even Yarvin agrees it wasn't worth the trouble. But he didn't just pull this idea out of nowhere