The point of raising the TR is to give it a better moment arm about the C of G. The horizontal component of the MR thrust is trying to roll the fuselage left about the C of G so mounting the TR high gives it an equivalent lever in the opposite direction.
If you are building a helicopter that will spend most of its working life in the hover, it makes sense raise the TR to produce a more level (laterally) hover attitude which keeps the cabin floor level and stops things like winch cables fouling the fuselage (see the Merlin/Cormorant for this problem).
If you are building a helicopter for high speed cruising then you probably won't bother to raise the TR as it adds weight and another gearbox at the back end.
Battlefield helicopters do benefit from having a higher TR as it is safer both from ground clearance and troop clearance poits of view.