Counter-opinion here: I am the maintainer of one of the most popular plugin for Next.js, and I am cruelly lacking data about how the users of my plugin use it, that would allow me to choose better defaults for it.

I don't have access to the Next.js telemetry data, but I could definitely need to ask the Next.js team from time to time: "so, are your users more using Yarn workspaces? Or npm link? Or something else?", etc.

For the same reasons some people complains about Ubuntu removing some features because they say "people don't use it", while people using those features tend to disable the telemetry. Sometimes, telemetry is useful.

It is not to spy on users, it is about making the best technical choices to ensure the best Developer Experience.

_edit: typos_