I do it because I get a 1-3% rebate on all my purchases. That's free money for me.
Before I had a credit card that gave me a rebate, I bought everything with a debit card. I still had a credit card, but it was only for emergencies.
> Still, the whole system of taking on debt for every minor purchase, just to prove that you'll pay it back, is sort of absurd.
You don't really need to use the credit card to establish credit history. Simply having one is enough. A lot of people believe that to maximize the boost to your credit score, you shouldn't completely pay off the card, and instead carry a small balance every month, but that's a myth.