Once upon a time, Qt was GPL + commercial. A separate project - PyQt - came and was GPL + commercial too.

Later, Qt became GPL + LGPL + commercial. However, PyQt, didn't want to add LGPL and stayed dual licensed. Qt thought "ok then, will have to do it by myself" and created an alternative to PyQt called PySide, which was GPL + LGPL + commercial.

That was in Qt4 time. Then Qt5 came, and PyQt5 appeared, while PySide was still in Qt4 land.

Then PySide2 happened, now known as Qt for Python.

PySide came to exist because Nokia failed to reach a commercial licensing agreement with Riverbank (the makers of PyQt). I guess one side or the other was asking for too much

https://wiki.qt.io/PySide_FAQ

> Initial research into Python bindings for Qt involved speaking with Riverbank Computing, the makers of PyQt. We had several discussions with them to see if it was possible to use PyQt to achieve our goals. Unfortunately, a common agreement could not be found , so in the end we decided to proceed with PySide.

And GPL isn't permissive.

Eg. that you can use it for free(?)

This seems easily googleable. Are you really completely oblivious as to controversy surrounding the GPL, especially as opposed to LGPL and ASL/MIT/BSD?