Some Simplesnap background: It does let you swap a controller between projects and electrically it works great. But it turns out that combined snaps are very strong, so it can be difficult to pry apart. We hoped to try the same thing with magnets but the tech wasn't there yet.
Not saying I had anything to do with it, but since I featured SimpleSnap screen protectors on the channel, I'm starting to see a SHIT load of screen protectors with installation trays on Amazon!