Your country must be really flat. Increasing the speed using the cruise while going uphill definitely takes a while here, same for reducing the speed while going downhill.

 

But, the biggest advantage to me is the ability to see the stored value after you've had the cruise deactivated for a while, like when you hit a queue for a while - after a couple of minutes of stop-and-go I never remember what I set the cruise to prior to the queue forming. Then, when it dissolves I just glance at the display and hit "resume" if it's set right.

You know Scotland, so flat it makes the Netherlands look like the Himalayas.

 

If the mod helps you, and doesn't inconvenience other road users, then it's all good.