It doesn’t mandate only local networking. It does mandate at least local networking. You shouldn’t assume there is no cloud abilities for matter devices. Eg a

It doesn’t mandate only local networking. It does mandate at least local networking. You shouldn’t assume there is no cloud abilities for matter devices. Eg a lightbulb will have to talk over lan to a hub/controller for on/off/etc, but for non-matter features (eg sync to music) it can still talk to the cloud. Yes you should be able to ignore these features, but in many cases you’re still putting it on your network so it’s free to talk to whoever (by default). In fact, several companies (Philips hue, SmartThings) have already stated that their matter devices will still have non-matter features that are tied to proprietary cloud APIs.