"Don't install on the system Python"

[John Ladasky]

Long-time Ubuntu user here.

For years, I've read warnings about not installing one's personal stack of Python modules on top of the system Python.  It is possible to corrupt the OS, or so I've gathered.

Well, I've never heeded this advice, and so far nothing bad has happened to me.  I don't like Anaconda, or virtual environments in general.  I don't like heavyweight IDE's.  I like to be able to type "python3" at the command prompt and be sure what I'll be getting.  I have multiple user accounts on a system that I manage, and I want every user account to have access to the same modules.

Maybe the modules that I require are safe to install on the system Python, I'm not sure.  My must-haves are mostly scientific computing and data management modules: Numpy, Scipy, Scikit-learn, Matplotlib, Pandas, Biopython, and Tensorflow.  I also use PyQt5 from time to time.

Can anyone provide concrete examples of problems arising from installing modules on top of the system Python?  Am I courting disaster?

Thanks for your advice.