They also are often used as performance pieces. A politician introducing a bill that is doomed to failure is not helpful, nor does it accomplish anything.

"Oh but it's important that they introduce them so that when congressmen vote no we have a record and-"

Shut. The. Fuck. Up. If I have to hear the "important to have a record" argument again I'm gonna scream. It is not important to have a record because the record doesn't mean shit. We've had records going back decades, it doesn't sway people in any meaningful way and it's foolish to pretend it does.