Mac OS X (because NeXT) switched packaging format from resource forks to directory hives, which are just as alien a concept, but with the advantage that most tools that silently ignore the resource fork will work correctly on directories.
Stuffit is, AFAIK, dead. Along with all the various other OS9-era packaging formats for resource fork files. If you need to send a directory hive over something that only accepts individual files you send a disk image or ZIP archive, both of which macOS will happily extract for you.
I vouched because nothing you said seems incorrect on its face, and i don't know enough to incorrect you. Someone else could; rather than no discussion.
It is good to know you no longer have to binhex mac stuff before zipping (and i assume tar, etc). That's why i sounded incredulous, even though the last time i used a mac the "install" was "drag this icon onto your hard drive icon"
I'm curious, if you have a disk/disc, and you drag a file onto the desktop, and eject the disk, does the file still disappear?
Stuffit is, AFAIK, dead. Along with all the various other OS9-era packaging formats for resource fork files. If you need to send a directory hive over something that only accepts individual files you send a disk image or ZIP archive, both of which macOS will happily extract for you.