At least even a relatively poor first generation evf allows you to see the whole scene. I remember framing my DSLR shots to account for the parts of the scene I couldn't see which would be visible in the final image.
I suppose my background in electronics helped me to be more accepting and transition from ovf to evf better than some but even so reading some of the comments on forums about how poor evf's are and how wonderful and so much superior ovf's are I often wonder what people have been using. I think that some people perhaps put on the rose tinted when talking about ovf's and overlook the downfalls and downright poor whilst perhaps tending to be far more critical of the newer technology evf's and failing to consider the positive attributes and judge them fairly.
All MHO of course
I suspect there is a fair amount of failing to compare like for like, and also each has strengths and weaknesses which depend on what and how you are shooting.
If you have only used a cheap EVF from 5 years ago, an OVF will seem much superior
If you have only used an entry level pentamirror OVF with cropped view of the scene, a modern 100 EVF will seem much superior.
An EVF can give a lot of ancillary information, and can adjust the view to reflect camera settings
An OVF is flicker free, making you feel less 'disconnect' from the scene (and making tracking at high FPS easier - though the latest Sony A99ii has supposedly fixed this issue with its 8fps EVF mode).
When I tried the A99ii I found the 'EVF experience' to be much closer to that of the A900 OVF (FF, bright 100%) than any I had tried before, no visible flicker (indoors in mixed lighting), customisable information overlays, etc. A big step up from the EVF in my more modest A6000, which while nice, lacked the 'refinement' I found in the A99ii EVF.
There may still be situations where the OVF is superior, but the progression in EVF over the last 5-10 years means that these situations are becoming less and less common.
I would need to get an A99ii and use it extensively to be fully confident,but it certainly seems that the EVF has 'come of age', and is a worthy alternative to an OVF in even a high end camera.