This effect drops off at higher power levels where decks are more likely to win through a combo than a mass of creatures, but this can stop many combos, like Glint-Horn Buccaneer, anything with Kiki-Jiki, Mirror Breaker, and combos that loop cards like Pyrite Spellbomb or Moonglove Extract for infinite damage
Later in the game, you can have a greater toolbox, with different exiled creatures that can provide card draw, bounce, removal, or just size
Most Expensive Lorcana Azurite Sea card list & price guide
Naturally I am laid back, so that plays a role
Unfortunately, some very rare cards, like the Espeon and Umbreon Star from Pop Series 5, do not have a TCGplayer market price, so they cannot be included
Being a Mega means it can make use of Mega Turbo to accelerate one Energy from the discard pile, and since this specific M Gardevoir-EX is part Psychic type, it can make use of the Dimension Valley Stadium to reduce its attack from an already low two Energy to just one