Regarding not being able to work outside the project root[0]: This is actually one of the things that I love about pipenv! Anaconda, for instance, has environments that are not tied to a directory and are referred to by name (rather than by a directory path) and I've found this to be an absolute nightmare and extremely cumbersome! Not everyone has 10 projects that can share the same environment. (Besides, I would argue they never should.) I, for instance, have 10 projects that all require a slightly different environment and it's much easier to type a generic `pipenv shell` on the command line no matter what project I'm in, rather than trying to remember the Conda environment's name time and again. (Besides, it can be easily automated using .bashrc.)
