That last ability, while pricey, is perfect for doubling up on ETB effects or swinging in with an extra threat to close out games
These Pokmon used GX attacks that activated extra effects if you attached a few more energies to them
Similarly, if The Soul Stone is already harnessed and becomes a copy of something else, it stays harnessed, though it's very likely that won't be relevant until that copy effect ends
It had already been decided that a trading card game was on the cards (pun intended), but before any official release, prototypes were made in order to test game mechanics and playability
Thats not always a given for green decks, so I imagine Synchronization will be very good in some shells, though worse on average than Cultivate
Consequently, any good Kitt Kanto deck is going to have a ton of ways to produce creature tokens, which you can then use to make your opponents attack one another