I used to work for a company that did them. Your usual deliverables would be paused, including meetings.

It wasn't "more". They were great. Most of our internal tooling was prototyped that way, and that tooling was super awesome... because it directly solved the real issues we had in our processes.

My current company is "you can during the designated hackathon events, but you still have to do everything you usually would". Which is absurd because it means that we don't always have the option to work late for free.

Good hackathons don't mean more work. They should carve out time for people to participate. However if the systems those employees are maintaining need constant work then you can't carve out time for a hackathon because the systems will go down otherwise. It sounds like Facebook is doing the latter. A one off event will also not improve morale, just like a pizza party won't on its own.

Hackathons are not working more. They’re supposed to be a liberal period to work on whatever seems interesting to the workers. In Meta’s early days, they were a big part of their culture and Zuck in particular fed on them.

I don’t expect everyone to know anything about Silicon Valley hackathons, but no, they’re not just “more work.” However when people are already crushed by what’s going on at work, they don’t have a lot of creative energy just looking for an outlet.