We have a GUI for one of the applications I work on that's written almost entirely in Python + PyQt. Everything voxmea said is true, for all good and all ill.

This module introduces how to develop Graphical User Interfaces (GUI) by ‘dragging and dropping’ various application parts in Python. Specifically, to accomplish this task a program called PyQt will ...

Streamlit lets you write web-based Python data applications without HTML, CSS, or JavaScript. Here's a first look at Streamlit.