There's no evidence the ban was a PR stunt, but it did play into Durov's hands, and through that, into the hands of the Kremlin when every dissident flocked to a service with centralized attack point to compromise all group chats -- the Telegram server.
I'm in a camp who thinks that this 'ban' was just a PR stunt coordinated with Roscomdanzor, which was known to be futile from the start and instantly raised the credibility of Telegram and cemented the myth how 'protected' it is.
[1] https://medium.com/@anton.rozenberg/friendship-betrayal-clai...