There are many ways in which to practice meditation. One of the more effective methods in which to cultivate an intentional journey within is by focusing on the breath. Since breathing is automatic, placing awareness on the rhythm of one’s inhalations and exhalations enables a person to more easily drop into that place of witnessing without attachment.
Deepak Chopra addresses the power behind breathing awareness and its use in meditation in this Q & A Intent post. According to Chopra, when it comes to meditation, effortlessness is essential. Using the breath as a vehicle, a person can transcend the limiting senses of perception.
You are quite right, establishing effortlessness in meditation is essential, and connecting the mind to the easy naturalness of breathing is an effective way to do that. But attention on the breath is just the vehicle for that actual experience of the Self, or the gap, which is without content and is not a function of the autonomic nervous system. The mind has an inherent tendency to settle down and experience its own source if it is given an opportunity by being undirected. Awareness of the breath or use of a mantra are vehicles that take attention out of the usual modes of directed attention through the senses of perception and allow the mind to be neutral and undirected. In that neutral state the mind will spontaneously be drawn inward to its silent essence, and that tendency is the driving mechanism of meditation.
Read more from Chopra on using the breath to cultivate meditation here.