Few technologies does not change easily,
One such is the mouse.
Technology changed rapidly over past few years. But it could not replace a mouse.
we can use our phone as an optical mouse. this is especially useful during travels (one less equipment).
Phone which has LED flash and rear camera can be used for this application.
A mobile application can use LED flash and camera just like an optical mouse.
This can be transferred to laptop over bluetooth.
Essentailly phone will get detected to laptop as a bluetooth mouse.