Telegram, really? From the guy who stored your passwords in cleartext: https://thehackernews.com/2016/06/vk-com-data-breach.html . Better have a look at https://en.wikipedia.org/wiki/Signal_(software) . It is Edward Snowden approved.
Telegram provides a much richer UI/UX than Signal or even Wire. [1] It has multi-device sync and multi-OS support. Signal lacks multi-device sync. Signal does not even have a proper desktop app. Signal explicitly prohibits backing up the data and restoring it if you move to a new phone/device (at least on iOS). The backup cannot be done to iCloud or even a local iTunes backup. So don't buy a new device ever if you like your chat logs. Or take screenshots of the chats for reference whenever you do. To me, this doesn't make any sense whatsoever. People want usability a lot more, and if a "super secure" app is not really being very useful, it won't get very popular. I'm still waiting for Signal to get ahead so I can switch to it, but every time I think of it, Telegram looks a few years ahead of Signal.
[1]: https://wire.com
It doesn't help that not everybody uses Chrome as their primary browser (I don't), making it somewhat silly to keep open for a single thing. Spinning Signal Desktop out into an Electron wrapper would be preferable but is still far beyond ideal...
> The same hacker who previously sold data dumps from MySpace, Tumblr, LinkedIn, and Fling.com, is now selling more than 100 Million VK.com records for just 1 Bitcoin (approx. US$580).
Ah, those were the days, when bitcoin was worth <$1,000.