It also adds green regardless of what your creature taps for, so you can tap for green and another color if you have a Birds of Paradise
While new cards from Ikoria: Lair of Behemoths that promote keyword counters and +1+1 counters could dampen the impact of Heartless Act in future Standard environments, at the moment, this modal card kills almost everything
Playing one of these could work well, with a couple cartouches to fill combat trick slots that offer long-game value with the trial
Across seven cards, you'll find art from Supplement I: Greyhawk (1975), Players Handbook (1978), the "Red Box" Basic Rules (1983), 2nd Edition Dungeon Master's Guide (1989), 3rd Edition Monster Manual (2000), 4th Edition Dungeon Master's Guide (2008), and 5th Edition Dungeon Master's Guide (2014)
I still strongly suspect I would play this over actual Coercion however