I am not sure what you mean by game-changing and I am not really a expert, but maybe I'll make some comments. First of all, my impression is that the Casimir effect is somewhat controversial, insofar as there are frequent disagreements on how to calculate it for different geometries. While the Casimir effect seems quite exotic, it may not be as esoteric a phenomenon as one might think. For example, a classical version of the same effect occurs between closely spaced ships with water waves replacing EM waves.
Also, at least according to one lecture I attended, one can treat the standard case of two parallel sheets of metal in two different ways. One is the Casimir way: EM fields with Dirichlet boundary conditions on the plates; long wavelengths cannot fit in between. The other way, is to model the constituent atoms and electrons of the plates and compute the van der Waals forces. According to the lecture I attended, one finds fairly convincing agreement between the two. This suggests that the Casimir calculation can be thought of as an effective (long wavelength/average) description.
It is this last point that is particularly relevant. Inside optical media, the propagation of light is altered on long wavelengths or in an effective description; however, at scales much smaller than the lattice spacing, the propagation returns to that of the vacuum. So I imagine that something similar could be said about the Casimir effect in this case.
In any case, I don't think anyone will ever be able to mine the vacuum, unless we are in a very long-lived metastable vacuum; in which case, it is decidedly ill-advised! Think Ice-9.