My car heats its battery below 60F, and it takes about 10 minutes.

A car needs to be ready to discharge at a much higher C than a house battery. So letting the house battery get a bit colder is fine.

Many electric cars have limitations on acceleration when the battery is cold.

Yes, I know.

My whole point is that cars are more demanding than houses.

So the house battery can tolerate a moderately lower temperature while meeting baseline performance.