These days you can barely walk through an airline terminal without someone from the airline trying to sell you on their credit card. One free checked bag, priority boarding, and various and sundry other "benefits" are pushed at you, but the question then becomes, is it really worth it?
To be honest, I don't believe most people think twice when it comes to signing up for a credit card. If it's free or it costs a modest annual fee, then why the heck not right? I was of that mind myself. My first airline credit card was a Citibank AAdvantage card which netted me miles on American. When I no longer flew American Airlines I signed up for the United Airlines Mileage Plus Explorer card. I was charging along happily for a while until I realized that I honestly couldn't be loyal to one airline all of the time. Sure, United worked for me when I lived in New Jersey and was flying in and out of Newark all of the time. But then I moved to California. United still works for me when I travel back east, but there are times I need to be flying places United doesn't go -- or doesn't go as cheaply as other carriers.
So I decided to get rid of my airline branded credit card and opt for a Capitol One Venture Card. With a Capitol One Venture Card, I can use my miles on any airline and I can also simply charge travel expenses and then use the miles to pay for them after the fact. This turns out to be a much better option when you don't want to or simply can't be loyal to one airline.
In fact, I don't have any store credit cards these days and use my Capitol One Venture Card for all of my purchases. While Kohl's or Nordstroms, Target, or any of the retailers pressure me to sign up for their card every time I shop at the store, the reality is that by keeping my purchases all on ONE single card, I'm accruing points that I can use to travel anywhere in the world.