The best way to take advantage of convenience checks that offer some additional incentive is, if you can afford it, to prepay the amount you intend to write, so the accrued finance charges are minimal. If there are no other fees (transfer fees, use fees, etc.), you should come out way ahead. I used to do this to swap balances from one card account to another but I wasn't aware any recent affinity cards still did this. I'll have to get a Citibank card.