I wish the Briar project well and congrats to them on this milestone. With that said, here is an essay I wrote in 2015 on "Why Encryption Use Is Problematical When Advocating For Social Change" (prompted from thinking about working for the Briar project):
https://pdfernhout.net/why-encryption-use-is-problematical-w...
"I believe decentralized knowledge sharing is important, especially for disaster preparedness. I also believe encryption is important in practice, the same way as many people have locks on their doors. Such things do affect a balance between state power and individual power, which is important in a democracy, and they also make it harder for vandals and criminals to operate. So, a project like Briar that supports decentralized communications and encryption is important for those and other reasons. Still, as my father (a machinist among other things) used to say, "Locks only keep honest people honest." Here is a partial list of all the ways a tool like Briar can fail when being used by activists engaged in controversial political actions. ..."
In short, there are many ways that your privacy can be compromised when using networked computers even if your software works perfectly at the application level --- from the hardware, to the firmware, to the OS, to the network stack, to user error, to people you communicate with being untrustworthy.
The conclusion: "If you want to build a mass movement, at some point, you need to engage people. In practice, for social psychology reasons, engaging people is very difficult, if not impossible, to do completely anonymously in an untraceable way. People have historically built mass movements without computers or the internet. It's not clear if the internet really makes this easier for activists or instead just for the status quo who wants to monitor them. If you work in public, you don't have to fear loss of secure communications because you never structure your movement to rely on them. If you rely on "secure" communications, then you may set yourself up to fail when such communications are compromised. If your point is to build a mass movement, then where should your focus be?"
In short, there are many ways that your privacy can be compromised when using networked computers even if your software works perfectly at the application level --- from the hardware, to the firmware, to the OS, to the network stack, to user error, to people you communicate with being untrustworthy.
The conclusion: "If you want to build a mass movement, at some point, you need to engage people. In practice, for social psychology reasons, engaging people is very difficult, if not impossible, to do completely anonymously in an untraceable way. People have historically built mass movements without computers or the internet. It's not clear if the internet really makes this easier for activists or instead just for the status quo who wants to monitor them. If you work in public, you don't have to fear loss of secure communications because you never structure your movement to rely on them. If you rely on "secure" communications, then you may set yourself up to fail when such communications are compromised. If your point is to build a mass movement, then where should your focus be?"