It might be "cheaper for them to use standard checks"--unless they are getting an "incentive" from someone who would profit from these troublesome cards. How about VISA and its charge to the merchant where you redeem your cards?
As for what "they usually do," you had better get used to these kinds of card-rebates. I just built a new computer and had three rebates from different companies, and these rebates came in the form of VISA card-rebates.
Rebate or no rebate, $25.00 plus free shipping is, as you say, "a solid price for the Verbatim discs."
Add to this the fact that I don't have to waste any more time and car expenses going to a store like Best Buy--only to find out that they are "Sold Out" on the first day of the sale! Again, Thank You, Newegg.