It's a matter of opinion if evf's are preferable to ovf's or not but a couple of things I'll now mention are not really opinions but are facts, although to give you some some wiggle room I'll say that these are facts IMO but in any case they may not matter to some people. They do matter to me so I apply significance to them
For example.
- evf's allow you to see detail in shadows and even in the dark which would be invisible with an unaided ovf or by eye.
- evf's allow you to see detail when using the magnified view that would be simply invisible with any unaided ovf system or by eye thus allowing you to focus very accurately, because you can see more detail and see what you're focusing on.
There are facts, advantages, disadvantages and about a ton of opinions on both sides so it's really up to each of us to make our own minds up but I do think that some of the criticisms of evf's and mirrorless are a little more hyperbole than grounded in objective comparison.