Because it does all voice recognition in-place by a highly specific chip. If you send out all voice data to a server, you're tapping into both CPU and radio, w

Because it does all voice recognition in-place by a highly specific chip. If you send out all voice data to a server, you're tapping into both CPU and radio, which is quite equivalent as when you speak on, say, Facetime audio or a VoIP app. I dare you to speak for more than a few hours with WhatsApp.