Where I see Python used is in places where you do not need it packaged as executables:
1. Linux - where the package manager solves the problem. I use multiple GUI apps written in python
2. On servers - e.g. Django web apps, where the the environment is set up per application
3. Code written for specific environments - even for specific hardware
4. One off installs - again, you have a specified target environment.
In none of the above cases do I find the environment to be fragile. On the other hand, if you are trying to distribute a Windows app to a large number of users I would expect it to be problematic.