Without a hint of irony, "Jane Tweedynn" astounded uk.finance on 09 Jul 2004 by announcing:
Because one generally has a maximum credit limit.
Not really. Spending 1000 a month on my Amex would get me up to 20 per month cashback. If I did the same on a 0% card, I'd still have to pay the
1000 back each month (due to having reached my credit limit on prior balance transfers and purchases) and not get any cashback.