I think you need to explain in more detail how that is significantly different from the pitch of a Pascal's Mugger - which usually doesn't make too much sense either.

It's easy to calculate the expected returns from buying a lottery ticket, and they're almost always negative. The psychology behind them is similar to a P-mugging, but only because people aren't very good at math -- eight-digit returns are compared against a one-digit outlay and scope insensitivity issues do their dirty work.

P-muggings like the one Eliezer described work differently: they postulate a return in utility (or, in some versions, avoided disutility) so vast that the small outlay in utility is meant to produce a positive expected return, as calculated by our usual decision theories, even after factoring in the very high probability that the P-mugger is lying, mistaken, or crazy. Whether or not it's possible for such a setup to be credible is debatable; as given it probably wouldn't work well in the wild, but I'd expect that to be due primarily to the way human risk aversion heuristics work.