This is the rsync v Dropbox of messaging applications.
Yes, unencrypted social features that could just as easily be serviced by any other social networking app which hasn't been explicitly banned yet (and that could happen to Telegram at any time).
> It's that Telegram operates under harsher network conditions.
So their operators claim. But it's not clear why that would be true and I haven't seen any numbers to demonstrate it either. Have you?
Telegram had to survive Russia's attempt to ban it, so it evolved a number of strategies: using push notifications to deliver IP-adresses of not-yet-blocked servers, using socks-proxies, the evolution of the MTProto Proxy encrypted protocol, and finally resorting to steganography to mimic ordinary https traffic, thus evading the DPI.
The attempts of the state censorship agency to block the telegram servers were hilarious to watch: at one point they had 0.5% of the IPv4 address space banned, and broke a lot of stuff (AWS, Google, DigitalOcean, OVH, etc). Telegram was still working, of course.
The IP-address delivery via push notification was a nice idea, if they'd only be on that level with their E2EE deployment.
The adversary in their case is mostly limited to beating up random people and picking on those that take a public stand against the regime.
Turns out it's more important that it works at all and not whether the security is perfect.
Supergroups and channels don't have expectation of privacy. They're not about protecting the content but about spreading sousveillance material, message etc. There only your anonymity matters so you can be safe with burner SIM + burner phone + Tor.
But immediately when you step into realm of confidentiality E2EE matters and Telegram becomes a piece of shit software. No E2EE for groups, desktop clients, or for anything by default. Small dissident groups greatly benefit from E2EE when Belarusian government can't read their conversation by just hacking a single server.
Both are important. Signal isn't about non-private mass-messaging like channels and supergroups so it's not going to offer those. Telegram could be fantastic for channels and supergroups if it used Tor by default and didn't ask for phone number. But it doesn't, and it tries to do too many things while ignoring too many security problems. Turns out that's a recipe to a disaster. See e.g. how CCA tracked Telegram users in Hong Kong, and how Telegram failed to enable the protective measures for users by default.
So, the fact that it happens to be a popular solution for encrypted chat right now doesn't really speak to its necessity for any revolution like you and the article seem to be implying. Easy access to encryption technology in general, sure, but that doesn't specifically need to be Telegram.