I spent a while last week second-guessing whether rolld was actually decentralized, or whether I'd quietly built something that leaned too hard on BoardGameGeek and on rolld itself.
The short version: your play records carry a small name snapshot ({ id, name }) instead of just a BGG id. That means every log you make reads as something a human recorded, on your own PDS, even if BGG disappeared or rolld went away. The cover art and ratings are still pulled from BGG, but that's garnish now, not the thing your data depends on.
I wrote up the whole thought process, the false dilemma I got stuck on and the three layers that got me unstuck, over on my blog:
Is my ATProto app actually decentralized?
Have a look if you're into that sort of thing. 🙂