Disclaimer : I'm neither of Whatsapp not Telegram (I resisted being on FB for longest time, even now - I occasionally visit FB)
I think importance of "Social Networks" is based on the user base.
So while security is important - if you are the only person on such social network, what does it matter ? You can't "share stuff" cause there aren't enough people there.
So moving to telegram makes sense only when enough of "your friends/family/relatives" are there.
