In Memoriam, FlyerTalk Evangelist
Join Date: Jul 2002
Location: Durham, NC (RDU/GSO/CLT)
Programs: AA EXP/MM, DL GM, UA Platinum, HH DIA, Hyatt Explorist, IHG Platinum, Marriott Titanium, Hertz PC
Posts: 33,856
I believe that airlines are more likely to help you in case of IRROPs or if you need a one time favor if they see the loyalty number on your BP. It shows you've made some effort, have room for growth, are knowledgeable etc.
Plus the tangible rewards others have outlined are great.