Thats important, however, even if this is the sort of card that loses value when it gets something else banned, like it did for Survival of the Fittest in Legacy
When previewed, there was plenty of discourse on whether the card should be legal given how much it shuts off your Commander
Black lets you fully discard the card, while white generally lets you exile the card from your opponent's hand and lets them play it for an extra mana cost
A single stun counter will be removed if the permanent tries to untap for any reason, including its controller's untap step, a spell or ability trying to untap it, or even its controller trying to untap it to pay a cost (although that one's unusual)
This includes casting artifact spells, paying costs to activate abilities of both artifact and nonartifact permanents, paying ward costs, and so on.
This class wont fly at high power levels where you cant wait around for the final level to take effect, but it works well at the mid-to-low power levels of most Commander games, and non-powered Cubes