Not only does having more cards in hand decrease the likelihood of you running out of things to play, but it also gives you a wider range of options for your turn
It was the first year we got Commander precons for licensed Universes Beyond properties, but Universes Beyond wasn't yet releasing tentpole sets or the like
The starting stats are terrible here, and this format neither has a ton of Clerics nor a ton of ways to gain life, and it needs both of those things to overcome it's problems
With this tin, you can choose the menacing grin of Mega Gengar ex or the whimsical wings of Mega Clefable ex, then find more Pokemon inside a handful of booster packs
Naturally, before battles you'll have to prepare your deck, possibly the most important part of the game
Feature Article - May 21, 2012 - Wayback Machine Announcing Planechase (2012 Edition)