The buffer system help to balance the PH of the body, introducing a weakly alkaline to the body, to neutralise the extra acidic is this a good thing?
Maintaining the pH is essential within the body, especially during digestion.
During the process of digestion, walls of the stomach release hydrochloric acid which activates the enzyme known as pepsinogen into pepsin, which plays a crucial role in the digestion of proteins.
But for the digestion of other components of the food, such as carbohydrates and fats, enzymes are secreted by pancrease. But for the functioning of these enzymes, alkaline medium is required. The acidity of the hydrochloric acid is therefore neutralised by the alkali, sodium bicarbonate, that is secreted by the walls of the stomach and pancrease.
This is just an example, but similar processes of neutralization of acidic media, in order to enable smooth functioning of the body take place.