If you focus on Electric cards, then Pikachu Ex can deliver 30 damage for every Electric Pokmon on your bench, equalling a total of 90
When combined with the power of electric type Pokemon like Miraidon ex, it could unlock a ton of power
It results in card disadvantage, leaving you with one fewer card in hand than before you played it, without adding anything to the board
(Also, if it has Infect and Toxic 1, it'll do four poison counters when it hits.) Mite Overseer is kind of weird, because it gives a Power boost which doesn't help at all with poisoning people, but it cranks out Toxic Tokens and the Power boost is fine, I guess
As the second triggered ability resolves, you must cast the card if able