Explanation
So you came here from the Google (or advanced Apple) setup guide and wonder why in the hell you should share your e-mail address with me. And that is a fair question. But actually, you don’t have to. If you choose the Home Assistant, Ubuntu, macOS, or basic Apple option (no control over the Internet), you don’t have to share anything about yourself with me.
But if you want to use the Google ecosystem, here is the explanation:
Most ecosystems need a special device, usually called a “hub,” to support Matter. In the Google ecosystem, a Google Nest Hub (2nd gen), Google Nest Hub Max, or Google WiFi Pro is needed, as of today.
In the case of Home Assistant, the “hub” is the Home Assistant server.
In the Apple ecosystem, if you want to remotely control your devices, you need an Apple TV 4K (latest generation) (with Ethernet and Thread support) or an Apple HomePod (latest generation).