bluetooth remote shutter button
I'm interested in getting one of these Bluetooth remote shutter buttons for my iPhone. Lots of semi-useless videos about how to use them, and I've never seen any written instructions. I understand that it's easy to couple them via Bluetooth to your iPhone, but WHAT MAKES THEM WORK AS A CAMERA SHUTTER BUTTON? Do they simply press your home button for you, and do whatever that home button is set to do? Or do you have to TELL the iPhone to use it for your camera? That is, what exactly connects these remote Bluetooth buttons to your home button? Or maybe, by default, they just press your home button remotely? Some smarts would be appreciated here.
iPhone SE (2nd generation)