Brython is a complete re-implementation of Python, thus it doesn't support some features/libraries (at least, it didn't when I tried it last), and is not compatible with C extensions.

The demo I put in the tweet is the same code as when you type `python3` in the terminal, just running in the browser. So it is much more compatible and is mostly [1] feature complete.

[1] minus whatever libraries are likely never to be used that we ripped out

See "Running Python in the Browser" [0] - I believe this approach is similar to Pyodide's.

[0] https://yasoob.me/2019/05/22/running-python-in-the-browser/