I have heard the argument that they get on a French motorway put cruise control on around 50mph and the fuel saved compared to stop start at junction etc helps off set the toll cost. How much it saves etc I have no idea, but must save tyres etc as well , in less braking and turning of the wheels.
I think that depends very much on what you're driving.
My previous van was Hymer S820 with a full automatic, there's no doubt it was happier cruising along at a constant 55-60mph, rather than accelerating 6 tonnes up a down every few miles at roundabouts.
My current van 3.5 Tonnes, 6 speed Sprintshift (same engine) is much happier on ordinary roads
Andrew