#1 weather sealing
#2 a lock DoF fonction (ring focus is so smooth).
#3 A non focus by wire ring focus but like manual lens.
#4 Highlights zones in liveview like Panasonic GX7 in EVF
#5 More noticeable histogram in OVF
OVF is really useful when you always use hyperfocal method. It can save a lot battery use because manual focus and OVF.