It is a matter of degree, but that degree is not small. Anytime you decrease the interval, you need to justify the commensurate loss of privacy. You can't just handwave away these concerns like posters in this thread are doing.

A rough inference of which months might involve vacations (data about which is probably already being sold from other sources) is far less invasive than a daily record of your sleep cycle.

With the lack of privacy laws in the US, it is pretty much a given that this data will be sold as soon as the private utility companies in the US start collecting it.