When doing the leg raises I don’t recall ever having heard about not letting your foot point up, something to do with the kneecap I think? Thanks.
It's not a big deal, but usually I do like to turn the leg slightly down so that it activates the glute medius. By letting the leg rotate up you're getting more glute Maximus, which is still good of course. So this form correction is not required, just a variation.