(I have a heat pump)
You can get electricity at 7.5pkWh. With a battery, I get 12h of cheap electricity per day, and the rest at higher prices.
At the coldest time of the year, I'm getting an average of 20pkWh.
This is just a fraction above break even gas/electric.
The rest of the year its no contest, heat pump wins.
My energy usage for heating is down by 60% year on year
My bills are the same as they were 3 years ago.