(1) better stability, better body position
(2) keeps up with 10 FPS
(3) better light blocking, never washed out
(4) better camera positioning, can track fast moving objects better
(5) better in tight areas were you don't have an arm's length
(6) better when you don't want everyone to see what you are doing
(7) better scene framing and blocking
(8) can frame even before camera is up and ready
(9) you don't look stupid with hands held out like some stupid tourist
(10) diopter adjustment so you don't need your reading glasses just to take a photo
bonus reason
(10) have you ever held a 300MM F2.8 zoom with hands extended out?
Bottom line is, for low performance, LCD's are OK. For real cameras, you need a viewfinder.
I would not pretend to tell anyone what type of camera they need
