I just had something of a revelation. Perhaps it's because I've become used to using my cameras with glasses on, but I never noticed how great electronic viewfinders are. The vast majority of people with sight problems are near-sighted, meaning they can see stuff that's up in their grill piece, but out on the horizon is a giant blur. Since optical viewfinders are precisely that, optical, the light going in is of the same distribution as that coming out of the viewfinder. So if the object is far away, you either use the diopter in the viewfinder or deal with using glasses.
Electornic VF's remove that need entirely. You can use glasses, not use glasses, it doesn't matter. The image is taken in by the camera and then reproduced less than an inch from your eye. The EVF's diopter is only necessary for those who are far-sighted. I love my EVF!