If I needed a message system that I knew would make messages unavailable after a few years because it was shut down by a company that never supports side projects this would be a valuable service.
That's ironic, because Google Chat to this day has migrated chats over from Hangouts and effectively served messaging for over a decade. But even Hangouts migrated chats over from Google Talk, which I personally used at least as far back as 2010.
To put that into perspective, Apple's iMessage has only been around since 2011.