While I will agree it's amazing and extremely helpful.... essential seems like a stretch. Plenty of photographers have created amazing images over the years without the "essential" data overlay on a EVF.

What I feel like, especially new photographers, are missing from the mirrorless experience is that almost forced learning. With DSLR cameras, what you see through the optical viewfinder isn't what you will get when you take the photo. You had to learn what the settings you chose would do, and often you had to learn by screwing it up. At least with DSLR you could take the shot, realise the settings weren't right and make adjustments then and there. With film, if you didn't get the settings correct there was no going back.

I feel like these "essential" overlays are (to some extent) replacing the need for photographers to learn the craft by doing a lot or allowing people to adjust settings to get a result without knowing why they got that result.

Maybe (probably) it's an old fashioned way of thinking. I'm still shooting DSLR because I don't NEED to upgrade and I'm not shooting professionally anymore. It's a hobby for me at the moment, and I know what I am doing. When I do get a new camera it will be a mirrorless one... maybe I'll think differently at that point. 🤔