It's necessery if you'd like discovering or if you're a false-beginner in the activity.
This means that you have to learn the skills, safe and effective behaviors with equipment (nodes, dynamic belaying, making relay, abseilng, etc.)
In addition to these manipulations adds the method and technical skills of climbing.
As soon as we acquire the rights movements, faster we improve ourself and climbing is more attractive. Gripping, put feet, casing, balance. In short, everything you need for climbing like a cat!