I’m not a developer, “I just have a dream”:
Here some information how Opera did it: http://www.opera.com/blogs/desktop/2017/03/telegram-joins-reborn-club/
They “just” integrated http://web.telegram.org into their GUI using this code: https://github.com/zhukov/webogram
Anyone here who would like to take over this integration? 
Thanks!
What’s added value gives Telegram integration?
What will be easier, what can be done with the integrated Telegram available what can’t be done now?
You’re right … I just thought about that and found no added values … 
Couldn’t the added be in the area of notifications?
Link Telegram with the Nextcloud account.
Now instead of email notifications in Telegram (instead of email).
Would be nice if this added (it’s possible as I use Telegram this way with another service 
)
BTW: do you know how a topic can be marked as answered/closed?
If so, please close the topic.
Cool idea! - But I think the effort to develop this does not make sense.
Why? It’s an open discussion … as you see you just found a point that would make sense to be integrated.
So let’s go on thinking about linking Telegram and Nextcloud … 
There are software bridges that can link XMPP to Telegram, thus with the JSXC Nextcloud app and your own XMPP server you can probably make it work reasonably well.
This integration could give access to unlimited personal Telegram storage for files, media.
I’m thinking of it as just another Secondary storage for Nextcloud.
Any thoughts?
You should have a look on the Two-Factor Gateway app which already provides Telegram support for sending 2FA token.