OFFICIAL TWITCH PLUGIN
Some of us have websites- eCom stores, information websites, etc. I have a PC hardware review website and would like to wish to integrate it just like Youtube. I wish Twitch had the tools that worked.
Twitch has embed code separately for viewing and chat. But it's rather a general code that has fixed width and height. You'd think a big platform like Twitch would have an official WordPress plugin with a responsive design. Also, plugins have better compatibility with WordPress.
There are plugins for Twitch, but they have long been discontinued. There are so many websites out there that use their own coding for responsive twitch stream and chat embedding on respective sites. They get a large audience and typically WordPress pages/ post has better search engine indexability and discoverability.
If you want to force people to join Twitch for complete interaction from websites, fair enough. omit the chatbox and have the view-only window, instead. This way people can view but if they want to interact they'll need to sign up and sign in. But at least have a WordPress plugin for an official responsive twitch stream window.