Somewhat counter to the article, I would argue that local first isn't about having "no cloud", it's "low cloud". So you could go P2P for sync, but you can also have a much more lightweight sync service on a central server. Both are valid "local first", it comes down to use case.
The way to think of the term is like when we all moved to designing web UI "mobile first". It's a kind of shift from operating one way and adding on support for the other, to the other way around. Start local and layer on server and cloud support.
One of the most exciting things about local first though is that once you have solved all the sync, and conflicting edit resolution problems (CRDTs are key here) you are 90% of the way to solving "multiplayer real-time". The only missing bit presence.
The community around local first is also really buzzy, it's got that great feeling of being part of something new, something that's going to be bigger than the sum of its parts.
To learn more about local first this is a great starting point https://localfirstweb.dev/