It reads like some sort of top-tier mana rock for typal decks, but its worse than the average 2-color Signet or Talisman, and its just strictly worse than Arcane Signet
That said, very little can beat opening a pack and finding these in the early days as the lore of their power had spread quickly among players
You can then begin building the likes of either Zapdos ex or Electrode to switch in once Pikachu ex is low on HP
It can be mass artifact animation, turning a bunch of Treasure and Clue tokens into creatures, though its an all-or-nothing ability that affects all your tokens
By, y'know, spending money on boosters
The land will retain any other types, subtypes, or supertypes it previously had