My analog is something along the lines of "please build a small room in your house, closet-sized at first, but with enough room to grow to twice that as we add features, so we can give you the best possible temperature and weather information. Also, we need access to your full contacts so you can share how you feel about the weather more easily, with just a push! Also also, we need a hot microphone in your closet, so you can shop our umbrella store by just talking to our AI assistant! Also also also, your privacy is important to us."

It only needs to be "an app" if it is using hardware to do it's main job. There is never another reason to make it an app.