So even their thinly-vailed claim of using the data for support and "issue diagnostics" falls flat, because they don't even provided support for the device at all. It's just data collection.
Even claiming it's for academic research datasets would be a better excuse.
Seems far more likely that they use a microservices architecture, and while they decommed the frontend that allows users to adjust their thermostats, they haven't bothered decomming the telemetry data ingestion services yet.
Even claiming it's for academic research datasets would be a better excuse.