Pulse is one of the last remaining of the group of PIN debit networks from the 1990s. Merchant service providers offer attractive bundled services to merchants allowing them to accept any card, PIN or signature, that the customer wants to use. Customers generally want to carry fewer cards and so carry the card accepted in the largest number of merchant locations, especially the locations where the customer regularly shops. Generally, that's going to be Visa or Mastercard rather than Pulse. Pulse suing Visa isn't going to change that and it seems unlikely to me that the courts will give credibility to the Pulse claims.