I'm not exaggerating but this might just be the highest impact library I've seen. As a backend developer who has lots of great project ideas but bail at the thought of having to use JavaScript and HTML, this library is a godsend! My only question is why it took so long for someone to implement it? And where are the equivalent libraries for Go, Rust and Java?
Not aware of anything yet for Go/Rust, but Java and Python have had libs like this for a while now (to the point that Pyjamas hasn't been updated in a decade):
* GWT (Java)
* Pyjamas (Python)
* Vaadin (Java)
Those are general purpose. After that you have the sci/data-oriented python frameworks like dash, streamlit, etc.