For example, the kettle boiled this amount of water this many times a day. The kettle isn't boiled between 6am and 6pm so we can deduce that nobody is home during those hours, but the autoboil function initiates at 5.30am on weekdays so we know the owner gets up early. On some Fridays it's later, so they either work more hours or they're off socializing. The quantities boiled suggest that only one person is drinking a hot drink most days. More water is boiled on Saturday mornings, suggesting that someone else spends the night on Friday. External access from the smartphone app comes from $provider but two different phones, suggesting that the drinker has access to two phones.
Now add in a name, phone number, and credit card usage data obtained from a third party, and suddenly you have something that someone will want. If it proves valuable enough, other manufacturers make a similar product, and suddenly a "dumb" kettle becomes much harder to get.