Those are kind of my thoughts too. However, I am newbie, so my expertise is limited.That's a good question. We are building a "Fort Knox" coop and run this coming spring to go inside our current "sort-of-protected", really semi free range, run. When we do, the plan is to leave the coop door to the run open 24/7 so they can go in and out at will. My thought was, if the run is predator safe, then why do they have to be locked in the coop.
I still want a pop door though. That way I can either lock them in or out if I need to do maintenance or clean.