Designing a "sexy" tablet is all about cutting those bezels thin, and for the iPad Air 2020, Apple has done a great job in that department. One useful thing that won't fit on the chin anymore though is the Touch ID button, so Apple's engineers had to find and implement a solution. Their answer was to build the Touch ID into the Power button that lies on the side of the device, and for this, Apple needed to revisit the sensor design.
So, the home button is now gone, and the Touch ID sensor has gotten rectangular, smaller, and hopefully even speedier. Whether or not users will find this better from a usability perspective, or will just accept it as a design-induced compromise, we'll have to wait and see.
More from Apple’s September Event 2020