Psi balls or simply speaking, a ball of energy formed in your hands, doesn't need to be seen. It is a way to practice energy techniques--training yourself how to push out energy, form it and hold it in one place (which takes concentration and focus). It gives you practice in being aware of your energy as well, on whatever level you can (be it purely mentally (in your head), empathic, or clairvoyant) Some guides tell you to reabsorb the energy (another useful technique) others tell you to send it up into the universe (which is a practice some people do with spells) and other instruct that the ball be given to the earth. The latter two teach sending energy to a desired location.
Of course with spellwork, the energy would be programmed for a particular task by your will, emotions/desires, and imagery. So you're going through the motions of magick without actually doing anything with it. Which is good because as a beginner, you shouldn't be doing anything with it just yet.
I don't believe in chakra work. Not that I deny there are energy points in particular places all aligned in the body, but I have found far more than 7 and I do not believe they should be prodded at. If a "chakra" is closed, its closed for a reason and that reason should be investigated and assessed in order to make that particular energy point healthy. That's my two cents.