Don't worry about someone reading your login details through the window any time soon, though. As the methods imply, a data thief would still have to breach the victim computer and have cameras they control within line of sight. This could be helpful for intelligence agencies performing Stuxnet-style intrusions, but an attacker can't just sit outside your home and read data from your computer monitor. Still, it gives ultra-secure facilities something to think about -- they might not want to place cameras behind air-gapped computers lest a rival nation pull off some Mission Impossible-level espionage.