[kccqzy]

The feature described divulges information such as "timestamps showing when it was unlocked, for how long, how many finger taps occurred, etc" which is absolutely personal information. And no, it is not privacy-preserving. It is an affront to all cryptographers to use the phrase "privacy-preserving" here given that it makes zero effort to preserve privacy.

Have you actually seen what amazing technologies are worthy of the name "privacy-preserving" these days? You can look up items in a database without the database operator knowing what you queried. You can let a server add two numbers without the server operator knowing what these two numbers are. These are worthy of the phrase "privacy-preserving" in this age.

[acdha]

That’s not a privacy risk under any normal definition of the term.