I have now installed two White 2-1 switches (and have a lot more to go).
The first switch doesn’t have relay click, despite me trying to turn it off and on (it was on by default) both via Home Assistant and via local settings.
The second one - to my surprise - has the relay click. On this one, I can’t turn it off.
If you are using a dumb switch, you can’t turn the “click” off. That’s because a dumb switch requires the Inovelli to use a mechanical relay, which is what you’re hearing. If you switch to an Aux, you can turn it off.
You can either enable or disable for single pole mode (user preferences). It’s more for switch feedback than anything important in a single mode setup.
I’ve tested a few switches and the single-pole ones seem to be clicking the relay just for the sound effect - and it’s impossible to disable it for multi-way switch. However, one of them seems to have the relay / relay click broken.