Question about creases.

When you increase the Mean crease on an edge is it only visually changed, like smooth shading? Or does it stay once you apply the subdivision modifier? For example if I were to create a model with the intention of 3D Printing it, when I export the file as an STL obviously the smooth shading would not carry over to the STL file. But if I had a Subdivision modifier and applied it during export it would smooth the file. So would the creased edges stay sharp at that point?