> such as optical quality

Huh? EVF and OVF have their own advantages but it is not correct to say optical quality of one is better than the other.

EVF can do things such as boost the exposure which makes things like the 800mm f/11 possible. This would be much too dark otherwise on an OVF.

EVF can also electronically correct the image for certain types of abberations that the lens introduce.

EVFs also don't introduce their own abberations that OVFs do because there isn't as much glass or mirrors to move the image from the lens to the viewer.

OVF certainly have advantage from being a "live" image for tracking purposes but EVFs have mostly caught up enough to make that difference negligible.

I'd still almost certainly take a DSLR OVF if other things were equal (which of course they're not).

But modern EVF is good for most purposes. And I'm sure the newest Canon digital bodies have even better ones than my Fujifilm X-E3. (Which itself is at least "good enough," while the X-E1 was more like "mostly sufficient.")

Personally I find resting the camera against my face and looking through the viewfinder to be more much comfortable than holding it out from my face and looking at the LCD. I can hold that position against my face basically indefinitely.

Absolutely. I'm talking about electric viewfinders that you look through just like you would an optical finder. Not using a back screen (although that can be useful too in certain circumstances).