such that a simple "$@" would fail miserably if nothing at all was passed

"fail miserably" meant (on my systems back then, anyway) that "" (a single empty argument) got passed instead of no arguments. It was considered more of a design quirk than a bug in my neighborhood, since it made sense for $@ to expand to something like foo" "bar (if two arguments were passed) but didn't make as much sense for $@ to make surrounding quotes, if present, just magically disappear (if no arguments passed).