alt Hacker NewsNot to mention it's really hard to statistically tell the difference between people spending a lot of time with a feature because it's really useful or because it's really difficult to get to do what you want
Telemetry is a really poor substitute for actually observing a couple of your users. But it's cheap and feels scientific and inclusive/fair (after all you are looking at everyone)
That is just poor analytics IMO, if you have a good harness you can definitely tell if a feature is not well designed. You have to optimize for things like number of clicks to perform an operation not time spent in app.