Difference Between Spatial and Nothingness Manipulations

This has been bothering me for quite some time, but I was thinking how Spatial and Nothingness Manipulations are so similar to each other. Nothingness is simply "void", which is to say: "spaces devoid of matter" or "empty spaces". Also, with spatial manipulation you can strike your opponent with space to reduce them to nothingness. Void and space are more or less the same definition. What does everyone else think?