And yet as a user I sometimes find local-first applications harder to reason about. For some apps I know to force-quit and relaunch the mobile app after reconnecting to the network before opening the website, for example.
Distributed systems are just hard I guess, especially involving user systems.
Local-first applications are much harder to reason about than server-driven apps or local-only apps, because there's now two sources of truth - the app and the server. Reconciling the two is much trickier than it looks.
I find that in most cases, a local-first application would have a more predictable UX, because most actions need to be successful without a remote server to begin with.
Still, building the UX with an "offline-first" mindset is a giant leap forward when compared to all the networked applications I interact with.