The power of this card is completely overblown
It's obvious when a clutch removal spell saves your bacon, but less clear when early pressure from a two-drop is what ensured your win
That attack deals 60 HP of damage for each Water Energy card you discard from your Pokemon, so you can adjust its power to whichever Pokemon youre facing
Finally, on the third turn, it becomes 5/4 Avatar Kyoshi, which gives your lands trample and hexproof, and then it can also be tapped to add X mana of one color based on the greatest power among creatures you control
More enablers for colorless instants are the impactful cost reduction, especially compared to spells with colored mana in their cost
For more set-specific examples, compare the top 10 cards from OP-13, top 10 cards from OP-15 and top 10 cards from OP-16 guides