If I say x=x+1.
What is x on the next tick if x was 0 to begin?
Lerp( self.x,target.x,something*dt) changes self.x because you told it to move some fraction(something*dt), or percent toward the target.x
If you change something*dt to 0 then it will move 0 percent of the interpolation(movement) of self.x, to target.x.
That is framerate dependent.
It is not meant to be pixel perfect, or to ever get exactly to target.x.