I stumbled upon an option to stream youtube to samsung smart tv.
PC/Android/IOS device connected to the same network as the Samsung smart TV
Scenario for PC:
Lets say you are browsing on youtube.com videos and you wanna watch it on a big tv screen.
Just click on the google cast extension icon during watching a particular youtube video, shows you option to which device you want to stream.
In my case Samsung TV appeared.
Chose your TV and you are done.
Chromecast is not needed.