[vanous]

The distribution packages are often carefully tuned to match compatible versions, with pip, you might add something that the packaging system doesn't account for. I disliked pip ever since but the virtualenv idea sounds good.

[maweki]

pip install --user and you have a local installation leaving everything untouched. As you have a local npm/cabal/gem package store.

[Annatar]

So now it is expected of me to learn some programming language's private packaging system, just to use an application?

Nope, that won't fly.