A Staggering Series Of Sales Now, on to the sale in question
Once you have these cards, you're also free to customize your deck as you see fit though you need to have a minimum of 40 and maximum of 60 cards per deck, not accounting for any extra cards like Fusion or Xyz monsters
The Charizard cards tend to become popular recently, which makes many desire to own at least one in their collection
Across a 20-pack box, that gives you about a 41% chance of pulling Akari Pikachu specifically meaning ~2 boxes get you to ~65% cumulative odds, and 3 boxes get you to ~80%
because the RL prevents WotC from printing new versions of those cards
A 4/4 creature for 5 is a reasonable rate as well, though as with most of blacks best mana doublers, being a creature is a pretty significant drawback with the amount of spot removal and board wipes flying around