Hi Bravlin, often it is not feasible with NURBS to smooth things out using control point editing because of how trim curves and "underlying surfaces" work.

When you do a boolean operation, surface control points do not change at all, instead the trim curves on surfaces are what changes. Trim curves mark areas areas of a surface as holes and in a model with trimmed surfaces you generally can't manipulate surface control points without opening up a hole.

There is some illustration of that here:
http://moi3d.com/faq#Q:_Why_does_show_points_work_for_some_objects_but_not_others.3F

It's a very different type of structure than polygon modeling.

- Michael