Yes, easier to see... to create an object with stroke and fill and try. Disassemble the stroke - it will turn into a curve with the casting. Disassemble the fill - will be a new curve with shading under the curve with stroke. Disassemble the object, it will turn from a managed object to curves. For example, if tresise picture - until it was dismantled you can play with settings of treysing. Or group interactive fill - until convertase it in curves you can interactively fill in the appropriate tools.