I agree with Mike. A bunch of people I work with have Alexa devices at home, and smart switches, and we all sit there and screw with the person at home. Phone roulette; a different phone every day.
There are things it would be nice if the App did, but in the over all it's one of the better apps out there. And no, you can't control an Alexa device with any app but the Amazon App. Doing so would also put a risk on your account info, cuz you know, the whole "Login" part.