As a teenager I stripped nearly all the screws holding the crankcase of my motorcycle together before realizing that JIS was different from Phillips. Didn't help that most of the old steel screws had seized against the aluminium crankcase. After a few unsuccessful attempts with an impact driver, I ended up just welding nuts to the heads, waiting for the heat to soak, then then wrenching them off. Then threw the lot out and replaced them with something sensible - stainless internal hex head screws. I guess the original theory for JIS was that its easier to replace a screw you've mangled then it is to replace the internal thread you stripped by over torquing it.