Please note that even despite the fact that a lot of details have seemingly "leaked," the Durov brothers have not officially confirmed anything yet.
First and foremost, Telegram is already a well-established messaging platform used around the world. Moreover, Pavel Durov is also famous for having created a "Russian Facebook," VKontakte. In my opinion, these two facts alone mean that there will be a host of people willing to invest.
Secondly, the launch of the Telegram Open Network (TON) could attract many more users to the messenger. The world's leading news outlets have already written about TON, while TechCrunch even dubbed it as "potentially one of the largest ICOs to date." The more individuals gain exposure to Telegram, the better for the messenger and Pavel Durov himself.
Given the fact that Telegram is serving more than 180 million active users at the moment, it has a great potential to create the world's most massively adopted cryptocurrency that could even "dethrone" bitcoin.
As we mentioned in one of our latest articles, what Telegram does really aim to do is create a new economy, where people will pay for goods and services with company's native digital token, and compete with large payment systems such as Visa and MasterCard.