Yep, you nailed it. That way you can have a wave propagate it's phase faster than light. The tunnel effect experiments I have seen all relate to this phase velocity. And really nothing new. A wave propagating in a gold or silver film will also see the real part of the refractive index being lower than one, and thus go faster than C. However, information can not go faster than light. The article mentioned here, is just a case of successful scientific advertising. It looks good, sounds good but really nothing new.