Having three mana dorks (including Deathrite) in the list is a little extreme given how cheap the deck is but two of them are doing other very useful things as well, some of the things you make are mana intense, it allows you to skimp a little more on lands and it gives you extra burst
card of cost for the purposes of playing cards
This gives all the probabilities of pulling a particular card in a Regular pack and a Rare pack
Trainer cards affect the game, players or Pokmon in different ways, most of them temporary, while Energy cards act as the resources in the game
Unlike Standard, you often dont have to have the wrath on turn 4, lest dying, so a little extra mana for a bonus effect is completely welcome, and Id say this bonus effect is extremely welcome