Refreshing the electro-magnetic actuator refreshes the full tactile display. It's sustainable and sensible and even economical. 

It's very useful in education especially when learning geometry, grasping basic coding concepts, playing instruments following the music notes, and etc. Because users are able to read a lot of information without having to scroll down every few words, it would be more convenient.

Most importantly, these tactile shapes and graphics will allow a more concrete concept of what these are for the blind who are never seen the graphic.