Youre not missing anything. Its a way of decluttering as the curves often tend to hide eachother making people confused. The IsoCurves appear when needed e.g. when in I-Form (see picture below). Aside form that most people are working in shaded mode (I believe) where Knots & Poles are avaiable - is there a need for combining? Do you have a workflow requiring that?
Hi @Sandman Thanks for your reply!