Can someone explain these to me?

When I do searches on eBay that involve jersey cards, I usually end up getting cards that manufactured. They aren't cards that you get from Upper Deck or Topps. Here's a Derek Jeter jersey cardI don't understand. National Sportscard Authenticators created the card, included a game-used jersey, threw it in slab and viola. Is there a market for these cards? Because at the price they are