You're right - I had heard of this "coupon" but never really understood what it was until you explained it so well, thank you.

It still baffles me though as they have entered into a contract with their credit provider which likely clearly says what payment methods are acceptable. A breach that contract seems to be undoing the very fabric of the narrative they're trying to weave with their sovcit nonsense.

Oh well, I've lost enough brain cells over this for one day, and my last one is getting lonely!