I agree with the other comments. Its super cool after it eventually loads.

For real world use I don't think its practical if its only goal is basic browser UX in Python versus JavaScript, but I can see amazing value in this for larger applications written in Python that need to make use of a Python GUI.

Absolutely. This shines when you actually want to display complex / animated / streaming data in larger applications; or if you want to create educative or training material on several pages (i.e apps here).

As an example, I once built an online stock/ticker app with it: smooth real-time updates in a nice plot. It would have been more complex with DOM based widgets (and probably less fun).