To add to a good post, part of the reason to NOT use most breakers as a switch is you derate (drop the ampacity) of the breaker over time due to wear. Add in a hot ambient (low save, sitting on the ramp on a sunny day, battery voltage drop, etc.) and the breaker can trip early/lower amperage.

Digression, but related.
Industrial environment, the company added a building with lots of lights. I suggested breaking up the light rows and putting them on lighting contactors but that added quite a bit of money.
The old plant manager stated, "We'll just use the breakers!".
A few years later (breakers switched twice a day, 5-6 days a week) we lost lights in the middle of summer as the building got hot.
Great money saver.......:-(