Yup, the REST feature is NICE! I use it as often as feasible.
As to staying warm, maybe. I do notice that the car heats up quickly & within a few short miles it can become a blast furnace inside. Even with temps below zero (like the past few days; we had a high of 3 in Cent. WI today) the car gets nice & toasty inside.
Ahhhh, warmth..........