I think that brakes off allows a smoother landing for the pax.
On the S-76 and other wheeled types I have flown, from a steady hover I feel that as the collective is lowered, the mainwheels need to rotate slightly backwards as the aircraft pitches nose down and settles vertically on the ground. If the wheelbrakes are on, all the pitching is done around the mainwheels once they make contact and the nosewheel seems to want to touch harder.