Smoke Alarms, Fire extinguishers, Defensive lumber, covered soffits, anything that will give an edge to stop a fire spreading and help people and buildings survive is all excellent and necessary. However, there is no guarantee that a smoke alarm is going to give the fire department the time needed to keep a house from being engulfed in flames. That will only get you out of the building, the fire will continue to burn, while you wait for them to show up. However, if the building doesn't burst into flames, you may be able to save it.
This was a good demonstration by the Fire Department:
See how the Eco building smokes, but doesn't catch fire, while the untreated building goes up in flames in a minute. As the Fire Chief said "I know which lumber I would use!"