I'd argue that depends entirely on the contents of the telemetry, which don't appear to be a part of this assessment. Besides (since this isn't about defaults), if you're configuring your browser to disable telemetry couldn't you just as well configure your firewall to block it?

Automatic updates also tend to leak information by design.

But anyway, this has nothing to do with my larger point. A good checklist would certainly have lots of boxes nobody ticks, this one was clearly built around firefox feature lists (and maybe others, but not chrome as site isolation is left out).