Using a cursor line following the mouse, not points, would be very useful know current cursor value (X axis value) to allow us to interpolate Y values and a way to set a JS method that will be fired on cursor move.
Is very common a table with the columns (Timestamp and Value), but in some analisys, is very useful "see" the value between 2 points. The value between this 2 points doesn't exist on dataset, but can be interpolated. With the current X value of cursor and a event will allow us to develop a JS interpolation method.