Putting telemetry in core to the side for a minute: the removal of telemetry from the Gutenberg beta plugin is odd. The purpose of that tracking as I understand it was to look at what blocks people use and what blocks are ignored. This is information of primary importance as Gutenberg is refined, and removing the ability to track that data means the team has to guess at how to prioritize and select blocks.

Most arguments against telemetry in core do not apply to the Gutenberg plugin: the plugin is beta, so any user would deliberately install it specifically to test it (and hopefully provide feedback), and telemetry in the plugin was opt-in.

I have not been able to find any explanation as to why the feature was removed from Gutenberg other than that it "probably" wouldn't have produced usable data - an assumption that begs numerous questions.

Considering one of the major critiques of Gutenberg is the overabundance of blocks and how hard it is to find the most useful blocks, telemetry seems not just appropriate but essential. It's removal is unfortunate.