Yeah definitely. I think the scope of desktop apps is often wider though.

With web apps any telemetry data is pretty much limited to things on that domain. Browsers have access to more in principle.

I guess if the data transmitted is not personally-identifying or profile-building then it's fine. E.g. number of sites only, not urls. On second glance at the new FF page https://www.mozilla.org/en-US/privacy/firefox/ it seems like the stuff they collect is pretty innocuous. Paranoia ftw.