The use of a smartphone in the realm of gyroscopes is that it can measure and maintain orientation. That means that the phone, being a stationary device, is able to monitor and actually control the orientation, direction,position and angular motion and even the rotation within the gyropscope.
When a gyroscope is applied to a smartphone, it offers recognition functions such as giving navigational assistance. The direction and the angle are what makes the smartphone and gyroscope work together in sync to reveal such navigation. This can aid in gettiing directions if lost or just to find out which way is north or south.
The two beautifully harmonize together to further science. As more technology developes, the simple invention of the gyroscope becomes even more useful and sophisticated.