Telemetry is generally a key component for quality assurance. While a paid tester can file bugs about "it crashes" or "it takes 10 seconds to load", a regression taking load times from 100ms to 200ms will be very hard (if not impossible) for a tester to notice and file a bug about. It will only show up in your telemetry.

You could argue that telemetry should then only exist in your beta channel or testing builds, and some developers do that. It's silly to argue everything can be caught by your QA team, that is simply not true for online services. In the past projects I've worked on have had long-standing bugs that took weeks of ongoing effort between both our paid QA staff and customers to finally identify reproduction steps, at which point we were able to examine telemetry for those reproductions and fix the problem.