Having a Telegram account means you are particular with security. Telegram is known for having a great respect to their users identity or personal information. Its a great tool for communication and instant broadcasting of ICO updates. Telegram have a huge number of followers. I know big companies are using Telegram as their way to communicate delicate information to their employees.
Its not the matter i think to make the success of the ico like what you said above.
Telegram follower is not about general but we talk about company follower mate.
Its right that the number of follower can measure the ico success or fail.