The typical power outage could leave you in the dark for hours or even days, while you worry about your food going bad and your comfort level suffers. An automatic transfer switch stops you from having to stress about the lack of power completely.
You don't even need to turn on the generator to get your power back when everyone else is dark. The transfer switch registers the lack of electricity flowing from the electrical tower. Once it detects that your house isn't getting anymore power, it switches the home backup generator on.