[AlexB138]

I keep two credit cards, the primary being an Amex. I do that because I like Amex's buyer protection, and their support has been between acceptable and impressive the few times I've had to deal with them. I keep a backup for when I can't use the Amex, similar to the above poster.

I do find it slightly annoying that I have to have a backup, but it's fairly rare that I need it, and the tradeoff is worth it for me.

I find it strange people are down voting what seems like an honest question about a pretty utilitarian matter.