They're not necessary, but they sure are useful. You get all sorts of perks, like fraud protection, extended warranties, etc, etc. You get cashback (or miles or

They're not necessary, but they sure are useful. You get all sorts of perks, like fraud protection, extended warranties, etc, etc. You get cashback (or miles or points, or whatever). All you need to do to stay in the black is to pay your balance at the end of the month. Best thing ever if you ask me.