the problem is that the Reserve doesn't get him into the priority pass lounges, which will be a big deal for an IAD-based flyer.
Good point, forgot about IAD. Though $550 + $195 (Amex Plat + Amex DL Plat) is starting add up on annual fees if you don't get value from the all that is offered.
Personally, I don't actually use the lounge a lot at LAX (my home airport) -- grab a cup of coffee if I have time. I'm usually there for a morning flight and too early (for me) to have a drink or beer. I live close enough to the airport that I am usually notified of significant delays before I leave home. But not everybody is that way.