Freedom to explore and get to know the subject
Getting to know the subject is a real plus of drawing freehand. We're allowing our pencils to explore the fundamental nature of the subject--not only shape, but its rhythm, the relationship of its parts--stuff of a good painting.
Freedom to compose
When drawing freehand, we can experiment with how best to place images in our compositions so each plays the strongest role possible. We can even enhance the composition a bit if we want to, to make it stronger.
Freedom to make discoveries
Many times a subject will contain hidden surprises that we would not have found by tracing, surprises discovered because of the close visual scrutiny freehand drawing requires.
Freedom from photos
There is no experience more invigorating than drawing from life, whether in plein air or a still life setup or just drawing stuff around us while stretched out in a recliner.
On the other hand...
Rather than give us freedom to create and discover, mechanical tracing only makes us depend upon it more. At best, it can only make the artist more insecure about working freehand. Dependency begets dependency, but freedom begets more
freedom.
