For instance, it can designate certain devices as 'slave mice'.

These mice can only be used for pointing in PowerPoint (without affecting the control of the master mouse).

In this case, the mouse buttons can be bound to different functions specific to the application.

For example, using the middle or right button to bring up a menu for drawing annotations, placing a pin, clearing markings, or using a magnifying glass specific to a particular mouse.

The magnifying glass feature would work as follows: click the middle button to turn it on/off, slide up while holding the middle button to enlarge the magnifying glass window or slide down to reduce its size, and use the scroll wheel to zoom in and out.