PSA: To all sellers: We live bh in a free country and you can set any price you want. However, most people have a cc which gives them 5x points on air travel (amex or citi etc). The values of those 5x points is usually around 7%.
There are also numerous benefits to buying airfare with a cc (protection, insurance and ability to pay later etc) which also add to the value of using a cc. For arguments sake let's say 3%.
If you are selling a gift card at less than min. 10% discount, there is no reason why anyone should bother to consider your wares....