An example method of indicating to a user that a biometric input was authenticated. The method is performed at a computing system comprising a processor, memory, a first housing that includes a primary display, and a second housing containing a physical keyboard, a touch-sensitive secondary display, and a biometric input device. The method includes displaying, at the primary display, a web page that identifies items for purchasing, and detecting a selection of an affordance displayed on the web page. In response, displaying, on touch-sensitive secondary display, an alert prompting a user to provide a biometric input to the biometric input device, and detecting a biometric input on the biometric input device that is in second housing. In response to detecting the biometric input, and in accordance with a determination that the biometric input has been authenticated, displaying on the display an indication that purchase of the items has been validated.