I use CC a lot.
Of course I tap on the decel button when I need to slow down.
I ususally leave about 4 seconds between clicks.
This slows me down so gradually that it almost matches the rate I would slow down coasting in neutral.
If I am going up a hill I will adjust speed down.
Down a steep hill I'll pop it into neutral.

So I guess I use a "hybrid" of cruise control and sort of a smart strategy.
But 95% of the time for my conditions I am in CC with both feet flat on the floor.

My lifetime avg for 27 tanks is 59.5 MPG for a 2004 HCH CVT that is one of the less efficient AT-PZEVs.
Not too bad.