Bright idea!
I tried this, and I found out that in order to make it easier to restore the curvature after deleting the joining ControlPoint one can first insert a Point in the position of the original joining ControlPoint (CP) before deleting the CP. Then InsertControlPoint back to the curve again, and snap into position when the CP is on top of the Point - then the curve will “jump back” to its original curvature again (well, pretty close anyway)
One may have to move the curve a bit after removing the joining CP as to make the curve to rebuild away the old cut, which is no problem since the position of the original ControlPoint is “stored” in the Point object.
Many thanks, this was a very useful idea!
// Rolf