Is it E2E by default yet?
Basically they are amassing an enormous amount of personal data, chat logs, etc. while their marketing and the public opinion is still that "Telegram is secure". That's a disaster waiting for the company to be acquired or turn evil.
What do you even mean by this?
Group chats aren't E2E encrypted and there is no way to enable it for them. In contrast, standard one-to-one chats are also insecure but there is the alternative of using secret chats with E2E encryption (however, unlike Signal chats, they don't synchronize among devices).
Then write something about that instead.
As recent developments have shown there is so extremely much more to security than just E2E-encryption.
iMessage approach is to treat every conversation as a group chat between all the recipient devices and all of yours. There's another risk here, that Apple doesn't let the end user verify the list of devices the chat is encrypted for.
Which is to say, a perfect E2E experience isn't trivial to design, but you don't have to drop the ball completely.
In the first row of the "Why telegram?" section, right in the middle, it says:
> Private
> Telegram messages are heavily encrypted and can self-destruct