In the latest PlayStation Blog, they highlight how the feature would work. The latest system update is a beta and the feature will soon be available to every as a distributed system update, but the feature will allow your 1 controller to be used with upto 4 devices.
This is achieved by assigning each device a face button on the PlayStation between the X, O, Triangle, and Square buttons which is similar to devices like the Logitech mice where you toggle between numbers to indicate a device.
This feature will be great if you have always wanted to use your PlayStation with other devices but are annoyed that you have to do the pairing process again when you want to play it with the PlayStation again. This could help make remote play easier to achieve as well.
