Three mana for four damage is the rate that decides whether this reads as removal or as a Food card, and in TMT it is removal first. The common toughness map sits at 2 and 3, with the occasional 2/4 out of green and white; four damage clears the entire common creature slot and most uncommons. It does not kill the mythic Turtle legends or Shredder, Unrelenting outright, but four to the body is real progress that a second damage source or a chump can finish off. That puts it at P1P4 to P1P6 for any red drafter, ahead of Bot Bashing Time, because the spent artifact stays on the battlefield as a Food for later triggers instead of going straight to the yard.
The self-damage is where the format softens the tension the identity blurb describes. TMT runs medium-speed: the red drafter is usually a UR Sneak build or a Mardu grind deck landing legendary creatures, not a one-drop shell stapling burn to a clock. Three to your own face on turn three rarely tilts a race you are already ahead in, and the otherwise-overpriced lifegain activation becomes a real off-ramp once you have spare mana and an Anchovy & Banana Pizza or Omni-Cheese Pizza already on the board.
The card sinks in value for exactly one drafter: mono-red Sneak aggro splashing nothing, which would rather run a creature and the cleaner Bot Bashing Time and cannot turn the three-life cost back into upside. Anywhere red touches an artifact or Food angle, it is a maindeck pick that buys a turn of tempo against a bomb, then becomes sacrifice fodder when a Food payoff wants it.

