What happened?
A curious gap in American commerce has been filled. Visa (NYSE:V) and Wal-Mart Stores' (NYSE:WMT) Sam's Club announced the former's credit cards will start to be accepted at Sam's Club outlets starting Feb. 1. Previously, only Visa debit and pre-paid products could be used for payment. The new agreement does not, however, cover online purchases at SamsClub.com.

The move is part of an initiative by the retailer to be more open to credit card sales. Last September, it began accepting American Express credit products for payment.

In addition to credit cards from the two giant brands, Sam's Club -- Walmart's warehouse club brand -- also accepts those from Discover Financial Services.

Does it matter?
The fight to get as many products accepted in as many retailers as possible has been a long one, and lately it seems that Visa is the brand scoring victories. Last year it won a big battle, replacing American Express as the only credit card brand accepted at Costco Wholesale stores in a deal that kicks in this April, and now it's joined the list of Sam's Club payment methods.

Sam's Club isn't Walmart (or Costco, for that matter). It doesn't have the size and scope to make a huge difference to Visa's results. We should also keep in mind that Visa (like archrival MasterCard) is only a processor of payments made through its products. It doesn't actually provide the credit, unlike American Express or Discover, and as such only books small fees on transactions.

Still, we can consider it a win nonetheless; the higher the acceptance rate, the more transactions it'll process and the more revenue it'll draw. The deal will have a bigger impact on Walmart's operations: Since Visa is the top credit card brand by volume in the U.S., it should rapidly become one of the most popular means of payment at Sam's Clubs.