I'll just add that mirrorless interchangeable lens cameras mostly became serious tools once electronic viewfinders became good enough that they could reasonably replace optical viewfinders for the most part. (Still not as good but a reasonable compromise given the smaller and lighter bodies they make possible.) As the say the LCD back can provide useful feedback--and are occasionally useful for specific situations when shooting--but at least for handheld shooting they're not often used for framing the subject.

And, to the original point of the discussion, these cameras also have lots of physical buttons and dials which are nice to have when they're properly designed.