I agree that devices should work independently. But I believe the fundamental baseline should be open interoperability. Yes, the dishwasher should allow a delayed start from the machine itself. But it should also have secure yet open interoperability so other authorised systems that care about the dishwasher can interact with it. I think there's ultimately a user experience benefit. I'm familiar with my phone, its UI paradigms etc. If I (or my gran) can use the dishwasher through an interface or voice assistant we're already familiar with then that's a win. Especially if the form factor of the device itself makes it challenging to deliver a great and intuitive interface in-situ.

In this regard CarPlay is evidence of success - a sufficiently interoperable car that allows users to bring their own context and ecosystems.

CarPlay is only evidence of failure if your expectation is that the car should provide a comparable ecosystem to Android or iOS - one that must also somehow follow you in your pocket when you leave the car.