That statistic is meaningless. The percentage of what's app users using a particular platform is far more important, assuming their customers matter to them. There are a lot of Nokia users on What's App. As far as iOS, with iMessage, what's app is redundant unless you have a lot of friends using another platform.
If there's a legitimate security benefit from What's App, then perhaps that's compelling, but trusting a Facebook company with anything remotely related to privacy and security is a fool's errand. Zuck has yet to prove that privacy and security matter.
For secure messaging I generally use a courier and a message written on paper using a one-time pad. Slower but more secure. If it goes over a wire, the odds of it being actually secure are low, unless you handle the encryption and control the keys yourself.
If there's a legitimate security benefit from What's App, then perhaps that's compelling, but trusting a Facebook company with anything remotely related to privacy and security is a fool's errand. Zuck has yet to prove that privacy and security matter.
For secure messaging I generally use a courier and a message written on paper using a one-time pad. Slower but more secure. If it goes over a wire, the odds of it being actually secure are low, unless you handle the encryption and control the keys yourself.