It's nice to have something that "just works" without having to install it. I like to call it Level 5 autonomous software -- software that can figure out how to run itself with zero complaints.

I actually use this for a lot of personal non-production scripts, I can just clone the script on any system and just run it, it will figure itself out.

Also, packages with version dependencies fuck up other packages with other version dependencies, unless you set up virtualenvs or dockers or condas for them, and those take additional steps.

magicimport.py uses virtualenv behind the scenes, so when it imports tornado 4.5 because some script wants 4.5, it won't mess up the 6.0 that's already on your system. In some sense it just automates the virtualenv and pip install process on-the-fly, to give the effect that the script "just works".