Interesting one, I think the difference is that you dont really control where your data is, it's like IPFS? I am surprised they managed to have queries, I will dig deeper into that thanks.
It's just a db, so your data is where the db is running. You could have a central db storing your data and your local client could sync periodically, or you can have a p2p architecture if you want. I use Noms as an embedded db in my project, where syncing happens between p2p nodes.