The seats are assigned. People have been standing in line for 15 minutes now. Why on earth would anyone want to stand there, when they could just sit and wait until the line clears?
I understand wanting to get off a plane ASAP, but boarding? You just end up sitting on the plane, waiting for everyone else to get on.
Now they’ve even started offering this at the check-in counter! Critically it’s after the “pay us $35 to check your bag” screen. It says it’s a one time special offer but I’ve done it a half dozen times now on American and twice on United. Bag just is supposed to be carry on sized. I don’t even have to take it through security when this option is available.