Wiring zbminil2 to always powered light

I have a smart bulb and a dumb light fixture installed on the same electrical circuit. I’m changing the switch that controls them to an inovelli zigbee blue 2-1 switch, so that I can leave the circuit always powered and easily control the smart bulb color.

However, I need to be able to turn my dumb light fixture on and off. I was thinking of installing a sonoff zbmini-L2 with the fixture, and then I can control the sonoff zbmini-l2 relay, and therefore the lightm remotely via zigbee.

The wiring instructions for the sonoff zbmini-l2 state, “Before installing the device, please install an air switch as the protective device(Air switch: 10A/250V).” and show a switch from S1 to S2, or from S2 to the mains line in.

Is this actually important? What does the switch do? My hope is to control the zbmini via homekit and home assistant, there won’t be a physical switch for it.

S1 and S2 are if you want a switch, so you can safely not mount or wire it if you don’t want a switch.