This is Samsung’s second take on a Dex docking pad. The first-gen version was the “Dex Station,” which held the phone upright. This new version lays the phone down flat so it can double as a touchpad if you don’t want to use a mouse.
Android apps can support keyboard and mouse controls, but most aren’t particularly well-optimized to take advantage of non-touchscreen interfaces. Samsung has a list of apps that are supposedly “Dex optimized,” and there are some heavy-hitting app developers signed up, like Google, Adobe, and Microsoft.
With Chromebooks bringing Android apps to a keyboard-and-mouse platform, too, more and more apps will hopefully start to support things like keyboard shortcuts and tab focus.