Collaborative usually means parallel edits of the same document by multiple people. More google docs, less chat room. I don’t think LV is well suited for that usecase. Usually it needs some kind of CRDT shared between clients, which is a good usecase for channels. LV however can supply the things around a CRDT based collaborative editing experience.

SPAs are an obvious choice for things like Google Docs, so drawing the line is tricky, but I want to point out that Livebook is a fully collaborative LiveView application, with rich text editor, visualizations, presence, etc. So LV could be a great choice for a collaborative app. It really depends on what you are building and the tradeoffs you are comfortable with.

Obviously offline support is a clear dealbreaker. The interesting thing about that in context of this convo is that Google Docs also doesn’t work offline. It swaps over to read-only mode as soon as the connection dies.
I can’t think of many web applications I use day to day that are offline capable. I also maintain that for the vast majority, just because SPAs are capable of offline mode, doesn’t mean folks actually implement it. You opt-in to a massive amount of complexity in doing so. That said, if you need it, you need it, but I find most folks don’t bother implementing it just because they can. So vast majority of web apps today are already on the network-on-the-interaction path.

Carrying on working while offline, optimistic updates that require pre-rendering the full UI element before hitting the server, and particularly large HTML documents are all things that would point towards client code rather than LV, bu there’s some gray area.