please allow me to give my opinion as a former csa and take it for what it is. there are alot of factors that determine why a passenger may decide to fly with xxx airline. as we all know, the main factor being $$$ however passengers also look at other things like non-stop flights/how many layovers, what airport they are laying over at(jfk and atl are generally the most hated from my experience working with pax), who had the latest accident/incident(you'll believe the amount of $h!t i've heard from pax), and customer service. there is a particular airline that i won't mention as it is my experience dealing with passengers that i used to get the most complains about and for that passengers chose to make that connection rather than the non stop flights. that is where the idea of giving amenities for the amount of miles flown with said airline comes into play. you get that passenger to fly for xxx amount of miles a year and he/she/it gets free upgrades, acknowledged as a member, a shiny card to put in there wallet and bag tag for their bag, and the right to b!tch and complain at their convenience(most members fly long enough to know the system therefore won't give csa/fa a hard time but then there are the few). so where i don't think csa has as much weight as the op may suggest, i do agree that it does have more credibility than most may think. and remember customer service is more than just the job of csa, it is for everyone.