The daughter just thinks about her mother for a while and comes to grasp that her Mom should have some sort of career, to be a more complete Mom. The fact that Mom is a witch rather confuses the story. To a child, is witchcraft a career? What does Mom actually do all day? Of course, real kids probably do not know what either of their parents do either.
Due to a rather serious lack of plot, the message of the story emerges without serious justification.
Working parents might make some use of this story, but there are better ways to make the point. That said, Tedd Arnold’s illustrations, as always, do a lot to make the book entertaining.