no, the SKIP_PYSIDE is needed when installing inside a virtualenv.
(The thing is, it's listed in requirements, so packaging tools will detect that dependency, but letting pip installing is a pain on the ass, so that var avoids the installation because it skips it during dep parsing).
On the other hand, when installing globally, we assume you already installed pyside as a dependency.
But I've been pondering about the convenience of removing it from deps and just say "hi, you should have this already installed or it just won't work". I'm not sure.