I was initially a little bit confused by Amazon's attempt to disrupt the mirror industry (and it seems like others in this thread are too). After reading through everything, my best guess for the motivation is:
> Echo Look helps you discover new brands and styles inspired by your lookbook
This feels like a marketing vehicle for high-end clothing and accessories. Maybe it's a way to leverage the reach of their Alexa ecosystem to compete with the likes of Polyvore?