Conclusion Any errata or banning of cards is sure to shake up a metagame
Its a good fit in lifegain/life drain decks, zombie typal decks, or even Bloomburrow -inspired bat decks that care about gaining and losing life
I appreciate that it can target itself
Mardu has a lot of access to artifact support, making Jan Jansen, Chaos Crafter a fantastic commander choice for Sacrifice decks in Mardu
I also really love the idea of making Taunting Kobold or Minion of the Mighty the Ring-bearer, letting them attack for great effect and not worry about being blocked
If poison-proliferate control takes off, this is a great way to remove creatures while furthering your ultimate win-con simultaneously, and that can make this a somewhat reasonable option but probably only for that kind of deck