Chromecast is first and foremost, a great product. It is very simple to use and setup is a breeze. Then, it makes use as simple as using the YouTube/Netflix/Play app on your phone/tablet. There isn't any new learning curve associated with it.
Then, the price point is just great. $35 is a steal for what it does.
It is also very thought out. It is very small and was the first product that I can think of that is just an hdmi dongle. Also, if your TV allows it, Chromecast can turn on your TV and switch the input to itself. Way too easy.