I found longer bangs to try and hide the forehead actually just makes things worse (way worse). It kind of shrinks the area of the face people have to view and makes people focus on the jaw / nose / even the brow WAY more.
If the hairline is right at the brow, the eye naturally gets to that hairline and stops.... meaning it is getting to the brow and stopping! Which is very bad. You want to draw peple PAST the brow, so they don't focus on it.
I dunno, each person is different... for some the long bangs might work i guess? I just have never seen it (and know it just makes things way worse for me.. .and artistically, it makes sense why).