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.
I’ve really never minded gate-checking, and when I travel alone (i.e. for work), I travel light and try to cram everything into a larger carryon and gate check it.
The biggest bottleneck on the way out is waiting at baggage claim. Gate checked bags are returned to you at the tarmac or at the end of the PBB, and sometimes they are there waiting for you before you even get to it, making it the quickest way out of the airport.