Given that they are a naturally sensitive area of the body, one can also imagine that taking a puck, ball or punch (MMA or boxing) could be unpleasant. While I'm no woman, I have it under good advisement that running (which causes bouncing) can be painful and that breasts can really get in the way of a proper golf swing. One thing that a woman's chest does not necessarily help with, however, is athletic endeavors. Large breasts can be used as a shelf, if one sits back at a correct angle. Sweater-meat also has some lesser-known uses. If you're a straight male, they are for other things that should not be mentioned in polite company.
The first two are pretty simple, if you're a female and have a child, they are for feeding. There are some great things about breasts.