This is why we need snakestagram so that the environment/kernel you want is bundled as part of nteract. You install nteract and it has a Python kernel + packages already there. Totally separate from what you already have installed on your machine. The files are somewhere inside the .app (on OSX) bundle that people install.
Do you know if there is a technical reason that makes it impossible to have widgets or requires a huge change in how things are done? My guess has always been that the reason it doesn’t exist is that there isn’t anyone who needs this badly enough to step up and build it (or pay someone to build it).