Amazon reveals private Alexa voice data files

I've never understood the charm of having an always on, listen to everything home assistants... Why? Just why?

To be honest though, I do have Google assistant on my phone and vibe recognition turned on... But at least that's an option. With these in home assistants, voice is the only mode!

So Amazon does keep these recordings server-side, indefinitely? Are we still to trust that they're only recording once the trigger-word is detected?