Why does Qt seem to need "resource files"? I mean the things you compile with pyside2-rcc resources.qrc -o resources.py, for example.
The documentation seems to say that it has something to do with accessing paths, abstracted in such a way that Python doesn't trip over the differences in a cross-platform application. But IME, Python does fine with Linux/Unix-style pathnames on Windows, especially if you use pathlib or os.path.join() or something.
In the days I used to use DOS, I found that command.com had problems with /, but you could binary-patch command.com to rename cd to something else, and use a cd.exe that worked with /'s fine - it was command.com that had the problem, not the underlying OS.
https://doc.qt.io/qtforpython/overviews/resources.html seems to say it has something to do with not losing files, which seems kinda odd.
So why does Qt need resource files, and can I safely skip them?
TL; DR; We are not required to use qresource, it is only an option.
It is not that Qt requires qresources on a mandatory basis, but rather that it is an option that in the world of Qt provides us. That is, using them or not in general does not bring a benefit or harm.
From a Qt/C++ point of view, resources allow us to embed resources within binaries. And this abstraction possibly avoids having problems with the directory system paths. And since PySide2 is a Qt wrapper it also tries to expose that tool.
And as you point out, there are several python libraries that already handle the paths in a generic way avoiding the known routing problems between OS so you could use it.