It’s used by a lot by organisations who want an alternative to Slack/Teams. Have a look at the client list for Element, arguably the biggest Matrix client/platform - https://element.io/

And as someone else mentioned there’s also a huge influx of IRC folks especially in the last year.

I don’t use it, but I imagine it sends mountains of telemetry and browsing data back to Redmond.

Juiciness?

I use Inoreader, works quite well for reddit.

I’m only a few hours in, but aside from the usual weird NPC behaviour this engine is known for I haven’t encountered any actual bugs so far.