This year I installed a heat pump with a 10kW auxiliary heater for my home in southern Ontario. With an appropriate air handler, both the heat pump and auxiliary heater can run at the same time. The setup seems fine to me.

If anything having a backup heat source makes me feel secure. A lot of things can go wrong with a gas furnace; some things can go wrong with a heat pump; but 10kW of electric restive heat is dead simple and just by itself it can provide 34000 BTU/h, which is 60% of the output of my old gas furnace. I don't think the duty cycle of my gas furnace ever exceeded 60% running time.

The auxiliary heater consists of two 5kW heaters, so even if one fails, there is still the other.