Character nostalgia is the dominant force here, with Gym Leaders like Misty, Sabrina, Blaine, and Giovanni lending their personalities and stories to cards that carry premiums far beyond what the Pokemon alone might command
These guys destroy all those nasty mana reflections and protection cards people love running in EDH
Unlike Temporary Lockdown, Ultima is not vulnerable to Into the Flood Maw
Its got a great pair of Attacks including the excellent Hydro Lander, which costs just one Fighting Energy to use, yet does 160 HP of Damage and allows you to grab up to three Fighting Energy cards from your discard pile, then add them to your Benched Pokemon in any way you like
That is such a niche reference, but the girlies who get it, get it