This is one of the super-powers of the Mirrorless cameras. You take a shot, and it appears in the eyepiece. No need to move at all, lose your subject, recompose, etc. This is super useful for macro and super macro shots. Combine it with a 45deg viewfinder and you can't beat it.
I never use the LCD screen back at all. As a result, the Z8 battery life is amazing. Four dives and 1000 images are no problem.