Like others have said, I could understand if PUG had any lore/reason for using magic, if even slightly, but there is none of that. If they decide to keep the MP cost I hope they explain how PUGs rely on magic (even if in a limited role) to help them.

Personally, based on their money-grubbing ways, I think it would be cooler if abilities used gil rather than mp (thinking Setzer from FFVI- coin toss anyone?).