This exactly. That's why I always pay cash, incl. tips. A charge on a credit card is essentially a loan from the Credit Card Company at the agreed upon interest rate. So I'm not comfortable taking out a loan to pay for my food -- granted you don't pay any interest if you pay your bills in full on time, but still it just feels wrong.
I also pay cash because I want the wait staff to get the entire tip amount I leave -- usually generous around 25% to 30% minimum. Because I was told by several waiters (mostly at Indian / Pakistani restaurants here in San Francisco) that if the tip is left on the card, that they never see it ever * .
[ * A waiter friend at Dosa on Fillmore told me this is illegal and that I should report it. Who do I report it to? And will they really take action? In a couple of Indian restaurants in downtown, the wait staff doesn't get the cash tip either. 1 waiter friend discouraged me from leaving any tip because they don't get a single penny. I tried to insert some cash in his pocket and he got scared. I think the owners forbid them from taking any cash from customers even if it's tip ]