Because once a card leaves the stack again, it is no longer considered a spell, and those target spell effects have missed another chance
The more packs players open, the more likely they are to get the cards they have been seeking
So if you use this card in your deck, you'll want to have multiple in your deck, and make sure to have at least 3 to 5 cards in your deck that know the Round move, that way you can put those Pokemon on your bench, and when you have enough energy cards to attack with one of them, move that Pokemon into play and use their Round move
Utilizing these cards correctly can allow players to gain the upper hand in a single turn , potentially knocking out a bunch of their opponent's active and benched Pokmon with one attack
Vaporeon follows suit with its anti-ex Move