My Amazon Acer C720 purchase was legit in the sense you're talking about. I saw a cheap box that could stream my Amazon Prime video to my TV's HDMI port and serve as a backup mail and browser system when it wasn't doing that; but the expectation was that it would sit on that pile of boxes next to the TV and live there. I bought it as a ChromeOS machine and it worked great for that.
Only after I got it did I discover I could put Crouton on it and have a full-fledged Linux system just like I'm using on my main machines, and that it really did get 10 hours on the battery. Now it's the one that goes with me on trips instead of my monster ASUS laptop whose power brick weighs as much as the Chromebook, and I can still do my C development and testing on it with no problem.