I'm (very) skeptical too, though if you were going to use this device (app) heavily, and it wanted to be always on, and power hungry, it needs more permissions than "an app" might allow, and it needs more battery too. Most likely it would still connect with the phone, but it would be like external GPS is for digital cameras - does one-ish function and does not drain the battery of the main device.

So maybe what they'll really get everyone to do is walk around with a second battery that bypasses some permissions, in terms of always listening or always using a camera. "Just an app" can never do that.

Funny enough people stopped buying external GPS for digital cameras because... your phone can do that now, as an app