I'm pretty sure MNT is added to the discussion because people here such as Eliezer and Annisimov and Vassar believe it to be both possible and a likely thing for AI to do.

Whether or not MNT is a likely tool of AI (I think it is), IIRC it is usually used as a lower bound on what an AI can do. This answers leplen's objection that MNT is a burdensome detail -- saying "AI could, for example, use MNT to take over the world", is only as burdensome as the claim that MNT or some other similarly powerful technologies are possible.