Of the three, it is the most legitimate "split" card
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A colorless source of fixing is a nice thing to have around, and this format has enough multicolored stuff going on that solving this isnt impossible, and obviously the Case itself increases your chances of having a deck that lets you solve this, but I still think this will be hard enough to solve that most of the value just comes from its ability to fix your mana, with some occasional late-game upside
Weapons Vendor makes it trivial to attach an equipment every turn, leaving plenty of mana available to play non-equipment spells you exile with Nahiri
Within hours of the reveals, prices for each card on TCGPlayer's marketplace started climbing up
However, it could be very interesting if it were optional, and if we wanted we could opt for card advantage instead of keeping lives safe, but I think that would be too much to ask