My company is a Windows shop, and nearly everyone who isn't a developer (so nearly my entire internal customer base) does not have Python installed.
I want to be able to send over single file executables that have everything they need. I don't want to have to think about using pip, or distributing wheels, or making sure they have internet access, or if they have admin or not. And as internal tools, I can afford to deal with relatively large file sizes.
For example, I have a lot of tools that need numpy and scipy to accomplish their goals.
That all said, Gooey + PyInstaller typically does a good job at solving my problems.
Edit: after reading the docs for pyinstaller, it seems that this is exactly what it does. vxNsr was either confused about what gooey does, or, like me, got confused by the name "pyinstaller" and assumed it was a tool to help you install a python environment on Windows.