Theres a pretty good podcast on the topic if you’re interested https://overcast.fm/+Xn2zXxLf4

Hobby, I guess. E.g. here is a rather lively talk about it: http://lists.newtontalk.net/pipermail/newtontalk/2020-March/

Here's someone who uses it as a ticketing system. https://twitter.com/XioNYC/status/1162073057881722881