Is the image fidelity really good enough for that? I thought color e-ink had pretty limited bit-depth and gamut.
Still, there's a lot of details to consider and trade-ofs to make wrt/ content, and Spectra refresh is also dead-slow.
Perhaps to their credit, E-Ink isn't even trying to hide the refresh in their marketing material: https://www.youtube.com/watch?v=Hr_EQaqTK0M (second half has a lot of examples of poster-sized Spectra 6 and Spectra 3100 panels).