I agree that wearing headphones increases safety in terminal areas but it leads to funny situation on my ATR-42 when skipper decides to have a go at manual flight. Now I have to make selections on ACP with left hand and only F/O's PTT toggle switch which isn't mounted on yoke is on center pedestal - two left hands are definitively advantage here. What I do is leave hot boom mike to talk to capt and talk to ATC via hand held mike in right hand. Second PTT switch on right side panel or right side of coaming would make my life a bit easier but I guess that adding one switch and five feet of wiring would require too expensive certification to make economical sense.