It also adds dependency management. If one subdependency is library_a > 1.0, and another is library_b < 2.0 while also e.g. 2.1 exists, then it will try to find a version between 1.0 and 2.0. Pip doesn't do that.
So in my mind, that's what pipenv is -- pip, virtualenv, those two files, plus dependency management.
- One with direct dependencies (versions pinned) - One with direct dependencies + subdependencies (pip freeze output)
Am I being too naive ? (obviously yes if such tool as pipenv exists, but I'm trying to figure why people need *.lock files).