Pavel Durov, founder of Telegram, wrote about “why using WhatsApp is dangerous”, citing the attack against Jeff Bezos.
Second, there are backdoors. Enforcement agencies are not too happy with encryption, forcing app developers to secretly plant vulnerabilities in their apps. I know that because we’ve been approached by some of them – and refused to cooperate. As a result, Telegram is banned in some countries where WhatsApp has no issues with authorities, most suspiciously in Russia and Iran.