Exiling your creatures on death sounds like a downside, but getting to reanimate one for free every upkeep is massive
Sometimes these cards, designed to either support or stop a specific strategy, arent even good within their own context
Any player can pay four mana to remove one of those counters, and they can do it during any upkeep
I should point out that there's a huge amount of work that goes into making Magic great beyond game design
These cards often convey the biggest change in your expected win percentage per time that you sideboard them in, but they may get sideboarded in a relatively small percentage of the time
Its Mortal Shuriken Ability lets you discard a Basic Water Energy from your hand to place six damage counters on one of your opponents Pokmon, then deal up to 200 damage with a devastating Ninja Spinner attack