Fingerprint readers on laptops of old were the swipe type. These existed on smartphones before Apple added it to the iPhone. The trick of it was that the iPhone uses a touch sensor instead of a swipe, which works better. Of course, Apple didn't invent it. Another company did. Apple bought that company in an anticompetitive move so that no one else could use the tech. Interestingly enough, that's why the sensor didn't make it into the Nexus 6.