Largely unrelated to the rarity of a specific card (although the two can go hand-in-hand), these Pokmon card types instead represent different versions of Pokmon in the games world - from their basic starting forms to later evolutionary stages and even immensely powerful Mega Evolutions and other variants
While the Ursula, Deceiver of All card got an Enchanted version, Ursula, Deceiver did not, so this extended art promo gives it some equal love
This one presses the line a little, although its not one that I feel like Id need to make specific mention of in a pregame conversation unless its the commander
Finally, you can wipe the board of all but two creatures if you sacrifice it and a legendary artifact
It looks like this deck couldnt hold its own against most precons
The constraints of filling your deck with creatures are just a bit extreme