I'm really curious.
Lets say theoretically someone has all the advantages of an EVF.
They are walking beside me on the trail and we come across some birds willing to be photographed.
By the time you've raised the camera and fired off a few shots, how much time do these EVF viewfinders save you? How is the image better than the one I get? The problem I have with all this stuff, is I find the AF on my K-3 with the 55-300 very fast and in AV mode the camera does everything I want automatically, including focus really quickly on an eye if I choose to do so. So I'm not sure how some people's perception of easier translates into anything at all. Time saved, unlikely? Less stressful? I don't find photgraphy stressful. I higher keeper rate? Maybe, but I typically get the images I want so I'm not sure even that is a consideration.
I've not seen one image taken with an A9 where i said to myself, self, that must be an A9 image. I've yet stopped see an image that would tell my EVFs are anything but personal preference.
Search: Sony A9 | Flickr Search: Pentax K-3 | Flickr
If both EVF and OVF are capable of taking pretty much the same images, the rest of the discussion is pointless. "It's easier with an EVF" is a very subjective opinion. If I don't have trouble with an OVF, it's just irrelevant. It's not smart to go fixing problems you don't have.
I had three seconds to get images of this bird before it flew. I basically turned on the camera, raised the camera, put it to my eye and fired off a 3 shots in burst, all 100% in focus and focus was next to immediate. So tell me, why do I need an EVF? Why would an EVF have been better. As you can tell, I'm extremely suspicious.
My conclusion would be, an EVF is just un-necessary technology. I don't buy stuff just because it's there, it has to provide me with an advantage somehow.