He so deserved it. But back to magic. At Joker's question, Strange nods.

"I do," he simply responds. "And I want to see whatever you cast as well. For lack of a better term, I can see magic. If I become familiar enough with any angelic magic you learn, I can tell you if anyone at any of the other places we visit has something similar."

For most situations, Strange would try and fix the problem and teach Joker the magic himself. But, to everybody's surprise, he's acknowledging his limitations for once. He can't really do anything with regards to angels.