Just to clarify, it is more efficient to lower the set-point in the winter over night. The issue is when your thermostat is set to utilize aux heat if the delta is higher than your set point change in the morning. For example. If you change from 70 to 67 at night. In the morning when the set point goes back to 70, the thermostat is likely configured with an aux delta of 2 or 3 degrees. Meaning every morning the expensive resistive heater is running to raise your temp quickly.

Personally, for my home and climate in the area, I disabled aux heat entirely, unless the temperature is below 0f outside, or if it hasn't reached the set point within 2 hours. Recently had some cold weather and these settings worked well for my home.

I'm using an Ecobee, configurations will vary per thermostat. The big settings for me were using manual staging to configure the temperatures to engage aux, temps to lock it out, etc.