They blend a unique package of discard, counters, and removal to cover all angles, all while having a relatively fast clock thanks to Deaths Shadow and Kroxa
Then, of course, the 4/5 body that lifelinks is basically a Lyra Dawnbringer in black
The fact that you can block with this card then sacrifice it, and still get all this value, is what really pushes it over the top
The only thing getting in the way were bigger creatures, and even then it could be a strong blocker or help soften up a defender for a burn spelland half the time he would live either way
From the pre-game discussion about power levels or possible strategies to acclimatize everyone to each other's decks to making sure one's deck doesn't monopolize time at the table, these "rules" are in place to make sure everyone has a good time