Panties need to slide past stockings straps
Sure, if you are planning to spend the day out and about, suspender (garter) straps under your panties with clips pressed against the skin might be uncomfortable, But is that what you were planning to do when you chose your underwear?
Didn't you choose stockings instead of tights (pantiehose I think our US friends call them) for other reasons?
Surely no woman wants to spend too much time in the bathroom fighting to reattach their stockings after a pee? Yes I know, you can tug the panties sideways, leaving the stockings in place, but doesn't that make it difficult to use a tissue?
As a man, there are other advantages...using panties as a glove is a very erotic activity...slipping them back up her legs can be as arousing as sliding them down.
I know where I stand on the issue, what about you?