ATC prefer wheeled helicopters to ground taxi rather than air taxi - it keeps them on the same routes as FW and removes potential problems with downwash and FOD from a hovering helicopter - especially a heavy one.
From an operators point of view, it saves fuel.
Not when they make you join the queue of taxying fixed wing for a runway you don't actually need or want to use and are then obliged to allow for vortex wake separation. An extra fifteen or twenty minutes burning and turning prior to departure certainly doesn't save fuel. Sometimes a significant part our planned fuel reserve is used up before we even get to take off.