Fuel dumping for fixed-wing aircraft is only used because they can take off with more fuel than they can land with, so if there is an emergency shortly after takeoff, they may need to dump fuel to get down to landing weight. In a helicopter, if it will take off, it can land, and I ain't dumping fuel no matter what.
Well Gomer, if you are flying out of Dili, East Timor over 7000 foot mountains and you have an engine failure, you have 2 choices, dump fuel down to Single Engine weight or crash.
I would dump fuel. Remind me to never get into a helicopter with you as the pilot. The whole world ain't a flat swamp like Louisiana.