The Pyside based GUI code is very out of date, and has been mostly replaced by the demos, which rely only on opencv for visualizing. Pyside is a heavy dependency (1.1 GB on my machine, by far the largest), and as a backend library it doesn't make sense to force this download for users who likely have their own frontend. Trimming both the unmaintained extra code and the large dependency will help reduce the package size, increase the download speed, and prevent a confusing entrance point to the package.