Bitcoin mining really only affects the AMD side of things, and it's less the fact that the prices are going up and more the fact that there are none in stock because they're being bought up by bitcoin miners.
1070 is a nice card, might be the end side of the generation but it will still be real good. No new cards will come out till after the sale ends probably anyways
Etherium mining works decently enough on nvidia GPUs that people are starting to use them as the AMD prices skyrocketed.
Bitcoin mining and Etherium mining are slightly different, but the same general concept. (like OpenGL vs Hardware rendering or whatever, both make 3d graphics)