Why external speakers? Is easier to play them back in the phone! I tell you how it will start. A company finds out the way subliminal message can help people

Why external speakers? Is easier to play them back in the phone! I tell you how it will start. A company finds out the way subliminal message can help people to be better. They release an app, it works! They promise it will always be free. After a few years they sell it for 100 million to Facecook, Facecook keeps it free for a few years untill they find a way to make money. Voila!