Infinite combos in Magic are awesome (if you’re a Johnny). Planeswalker ultimate abilities are awesome (if you’re a Timmy). Combining the two would be even more awesome. Then you could have a billion emblems from Chandra, Torch of Defiance, Teferi, Hero of Dominaria, or Kiora, the Crashing Wave. Because dealing a billion damage isn’t as cool as doing it every time you cast a spell. And getting a billion krakens isn’t as cool as getting them every turn.
What’s the fewest number of cards (besides the planeswalker) that allows you to activate a planeswalker’s ultimate ability an arbitrary number of times?