Yeah I thought the same thing. Although, if Telegram is any indication, mass market is not a matter of how strong your implementation is, more of a marketing/business problem to be solved.
but its a lot more secure than some....
This in itself wouldn't even be that bad if they weren't then trying pretty hard to convince the general public that it's super secure with massively flawed stunts as explained here: https://moxie.org/blog/telegram-crypto-challenge/