While sleeves are certainly meant to protect your cards, using a playmat to keep them from picking up a bunch of gunk from your play surface never hurts
The ability to generate 1/1 tokens every turn is good, whilst the 3 power on a 4-drop is slightly understatted
However, only one VSTAR Power can be used by a player during the course of a match, making the choice and use of such an Ability highly tactical
The main downside to those spells is that they lose their power when your creatures are either too small or get removed, effectively rendering them useless
The final card type, Trainers, have various one-time effects and do not cost Energy
Overall, the Eevee Box strategy is incredibly versatile, but Flareon ex is by far the strategy's most important card