StuffIt is one of the worst parts of the classic Mac OS with its poor format compatibility and supremely annoying resource fork behaviour. (Makes you wish Zip was used instead.) Mitigating the damage (I’d be fine with 4.x archives since that works on 68000, but I’m a System 7 > 6 person anyways) of it is very handy.
I always dread dealing with weird mac formats from before OS X.
I don’t know how people tolerated or survived back then