in my opinion, the advantage of hanging a camera high is ONLY to prevent theft of it, and by High I mean like 8+ ft high!
and when you hang a camera that high you have to spend a LOT more time at the site, both hanging and checking
so in return your actually adding more scent to the area IMO
next I also think you can MISS more game being higher, pending the type of camera and its trigger zone
last is you can NOT get images of things due to distance added by going higher
me personally I say wear rubber gloves and try and be scent free when placing a cam out
if your worried about scent
and placing the camera on a OPEN side of a tree, it sticks out, so adding cover , say Pine tree limbs about the cam will do two things, will help cover scent, and break up the outline of the camera
even deer can see a NEW object on a blank tree trunk!
add in MOST camera's make some sound when they take a pic's and that is why I think you many times get pic's of deer looking at cam's in pic;s
over just scent!