One of the biggest crossovers was the special Pokmon McDonald's Happy Meals, which contained limited edition TCG card packs
The thing that pushes this to a level above cards like Impulse for me is that you can put things back into your deck and that is something not many cards in magic allow for, certainly not in such a cheap and painless way as this (except of course Brainstorm...)
His Shift 3 keyword ability means he can be played as early as turn three, and hes got several powerful abilities, letting you gain lore when he banishes characters, and letting you draw a card when hes banished
If you pull out a monster that is good in sea, once you move him upward into the wasteland, the monster's ATK will go down because Aqua monsters aren't favorable for wasteland terrain
So, in certain situations, Pokemon with the highest HP are ideal and thus worth seeking out