I downloaded this a few months back hoping that in NYC there would be enough user density to make it useful, but it seems I was too early. Interesting use case that protesting would be using it.
Would definitely be interesting to see it being used for entertainment purposes. But it appears its a "last resort" kind of app, especially with Hong Kong's situation.
If people are growing more and more concerned with privacy that could be the nudge. Or if they offered something standard SMS cannot (speed, feature, etc.)
A couple months ago I installed this on two devices and could not get it to work off-net nor did I see a good description of how it is supposed to work in that case. I assume Wi-Fi and Bluetooth on but not connected to an access point.