I don't know what the Windows installer does...
<img width="543" alt="python_installer_step1" src="https://user-images.githubusercontent.com/181177/95642229-0873ae00-0a5c-11eb-9d28-2ba05647e84a.png">
By default it only puts `py.exe` (and `pyw.exe`) into `%PATH%` (specifically, in `C:\Windows`), and not the normal binaries. In the installation directory (presumably added to `%PATH%` if the non-default option shown is ticked), only includes binaries called `python.exe` and `pythonw.exe`.