This could make it extremely easy. "What programming language should I use?" "Learn Python." "How do I install it?" "Through the Windows installer." Boom, done. They're off to the races.
People who want control and specifics are advanced enough to figure out how to get that themselves.
In what way does it screw over people who want more control? You don't have to get the python distribution from the Windows store.
It does help students/beginners/'people that want to hassle free install' get going with python.
For those that want to install the most recently released or a specific version number of the python installer, there's still the obvious channels and those people that would seek it out will know how to find it the normal way already. It's fine.
The possibility of a built-in one not being what you want adds a whole category of issues that wouldn't surface before. Maybe also those alternative ways of packaging die out due to lack of interest.
Ask folks who ran into this with an old release installed by default, as in a Mac. Some of them appear to be on the thread.