It's interesting math. You can turn natural gas into heat directly at around 90% if it's plumbed to the building. You can turn natural gas into electricity at around 50%. You can turn electricity into heat (resistive) at 100%. You can pump ambient heat inside using electricity at 300% (depending on several factors; adjust as appropriate).

Therefore the choice is between a gas furnace at 90%, or gas to electricity to a heat pump at 150%, if we care about the efficiency of gas usage between the two options.

But when comparing price per kWh of delivered gas vs electricity, ignore the 50% gas-to-electricity efficiency, because that's irrelevant. It's just the 90% vs 300%.

Therefore a gas furnace is cheaper if the delivered price per kWh of gas happens to be no more than 30% that of electricity in your area. Of course the rate for gas will more likely be in therms than kWh, but that's a simple conversion (1 therm = 29.3 kWh).

I suppose that's the case in Texas?