The centre of the object is still the same but now you have created a new axis point so in case you want to rotate now the object will rotate around the new axis point ie the line from new axis point to the object acts as radius.
Hopefully the images will explain better
You can move the center of an object away from it (image 1) .
That way if you want to rotate it etc the moved center will act as an axis point(image 2).
This is very helpful to create your own designs. For eg I used this to rotate around a circle (using ctrl c to copy and Ctlf F to paste in place) and made the shape (image 3)
Now you can see the possibilities.