It's just as much a problem that it's secured. If not more. The government security services can view government email at will. Employees relinquish the right to any privacy in government-business communication. (unless executive privilege is used for the select few, etc). If you use WhatsApp, the government loses that ability. Or at least makes it orders of magnitude harder. And beyond that it requires the security services to go before a judge to subpoena the property of private messaging/email services. And some libertarian-minded Silicon Valley companies have taken a hard line against turning over data to the government without exhausting every legal hurdle first, e.g. proving probable cause of a crime, etc. The security services should not have to do that to get the communications of government employees.