I don't know what "gimmicks" it may have which iMessage does not(although the in-chat polls are pretty handy), but IMO the big strength of Telegram is privacy.

I don't know what "gimmicks" it may have which iMessage does not(although the in-chat polls are pretty handy), but IMO the big strength of Telegram is privacy. You can use it without revealing your e-mail address or phone number. The situation of not knowing a single non-Apple user is unlikely outside the US anyhow.