As an exercise to see how wonderful these tools can be, use them to draw a rectangle with rounded corners as follows: With connected lines and snap to grid on, quickly draw a closed rectangle with 45 degree short segments in the corners (eight sides in all). Now adjust the position of the vertices if your quick draw needs it. Click the change to arc button on the utility toolbar and click on each of the four 45 degree corners. Presto, rounded corners of exactly the right radii!

Now if you want to alter the figure by dragging points, things will go wrong. Arcs will misbehave. Change all of the arcs back to line segments, drag the points and then convert back to arcs. The figure behaves when it is all segments.

This is how I have learned to draw shapes. Use connected line tool to put all of the vertices in the right places and then convert to arcs and splines. If I do need to edit a part of the figure, I convert the nearby arcs and splines to segments, edit, and then convert back.