So much of the car is automatic and anticipation dictates that you try not to stop, that it's easy to forget to apply the handbrake.
Not a problem normally, but not so good if somebody were to run into the back of you without the handbrake on ?
At 56 mph it's just below the maximum speed of some lorries, and cruise can always be used at less if you wish.
It's frustration playing tag at 56 mph on the inside lane, --- with the same lorry, for miles !