As long as you have the discipline to actually pay the thing off it's fine. Many people think, "oh I have 0% interest, I'll pay it off later" but never set aside the money to do so and end up accruing interest.

I never buy something on them I couldn't immediately pay off in full when I hit buy. I've bought things in excess of my checking balance, but that's because I had enough in savings (separate from my emergency fund), and my incoming paycheck would put my checking balance well above my credit card balance.