OK, I am in disagreement with a friend and would like your feedback.

At 3:00 this morning, a battery was dying in my smoke alarm and started
chirping. It makes my little dog shake like crazy. So, I had to go to
the garage, get the tall ladder, and remove the battery.

My friend said to just flip the switch at the fuse box and that will
take care of the chirping noise until I get up to put in a new battery.

If the battery is there to backup the smoke alarm during a power outage,
why would shutting off the switch in the fuse box keep the battery from
chirping?

Thanks.