It isn't an optimal card in these formats as of right now, but that doesn't mean that it won't become more popular if we see cheaper dragons down the road
This mechanic has been used sparingly in various Commander precons, and appears on the following cards: Crdan the Shipwright Elrond of the White Council Mob Verdict Trap the Trespassers Truth or Consequences The Council Will Decide Your Fate The Valeyard | Illustration by Tyukina Tatiana Well, we made it to the end
For example, equipping Heirloom Blade to an eldrazi token you made with Awakening Zone and sacrificing it to fetch up Ulamog, the Infinite Gyre is some spicy synergy I can get behind
It's unlikely you'll be forced to sacrifice it, you can disregard combat damage and nearly all burn spells, and if they can't deal with your virtue, you'll win the game on your terms
But dont look at this like its conditional to your tables discretion
When you do, ask a person outside the game Does this look balanced? If they say yes, you may tap or untap target creature