Any consumer-grade "smart" product (whether TV or home automation) now phones home (even though it can run entirely locally on the LAN), requires an account and collects data and the (often mandatory) mobile app will typically include various advertising malware such as the Facebook SDK, analytics, etc that spy on you.

The primary objective is "growth and engagement" aka an ad delivery mechanism (or data collection mechanism for more ads down the line). The functionality of the product (if any) is merely a necessary evil (from the manufacturer's point of view) to convince the mark to buy & "engage" with the device. If they could get people to "engage" with it without any functionality they'd definitely do that instead.