I would argue that opt-in telemetry is the worst you should think about. To improve your software, there are other means than mass surveillance of your users (

I would argue that opt-in telemetry is the worst you should think about. To improve your software, there are other means than mass surveillance of your users (e.g. lab-tests). And if you really need a lot of data, ask who wants to participate and also offer a solution that lets them participate for a limited amount of time. In my experience, you can find a lot of problems with lab tests and when your team disagrees about some findings, quantitative tests can help you find the correct answer. But tracking all your users constantly isn't necessary to reach a good user experience.