The single-player challenges are designed purely to help players understand how the games elemental system works - which is similar to that of the Pokmon video game series - and give them a chance to use various cards found in the wider game, which is great for helping to develop your sense of play and on-the-spot thinking
A listing nobody sees doesn't sell, especially with collectibles, where most demand comes from feeds and fan accounts rather than the marketplace itself
Overall, it gives you more opportunities to overpower your opponent
But what makes it better are a few key additions to the Shaman: It's potential card advantage that can push Red into the stratosphere with a mega-amount of card value
As such, the developers decided to give them their own battle theme, something that hadn't been done with the Rocket Executives or Magma & Aqua Admins
Im not seeing a whole lot of use for this one beyond being a cheap 13/13 in decks with life manipulation