I see nothing at your link which differs from information here.
You just have people arguing about the same two Verge/Wired stories on the tab casting.
Regardless that Wired didn't notice any issues with it, it is still a poor solution. Wired used it to play a TV show MKV, likely lower resolution so they may not have noticed the problems. They spent a whole 2 and half lines of text covering the feature.
Verge has more extensive coverage, including how it works. It plays the video locally on your computer, then uses WebRTC to essentially send screen caps to the device.
This is the critical part: it needs to recompress the video again in real time to send it to the chromecast.
That is bound to destroy quality for most people and cause hiccup on higher resolution materials.