There are many more. LIFE Breathing has much more to do with life than taking in oxygen. Much of the nervous system responds to the way the breath is taken in. If you breathe a lot in your belly you stimulate a more relaxed response to everything you see hear and feel. If you breathe into the high chest you stimulate the organs and muscles of action.
Balance is indispensable.
Many breathe in an unbalanced and labored manner. To not breathe easy is to overstimulate the organs and muscles of action. Like keeping your foot on the accelerator day in and day out, and one foot on the brake. Your engine is constantly at a higher rev than needed. To the degree one is motivated toward optimal breathing is the degree they will breathe easier and fuller.