The label on a product performs many functions including: identifying the product or brand, describing the product, promoting the product, and supporting it's positioning.
The label does these exact things but letting consumers know what product it is and often times, people make a decision to purchase something based off the label. They are familiar with the product they see everywhere and recognize its brand identity based off of that. If detergent, for example, were all lined up on a shelf and nothing was labeled, a customer probably wouldn't be able to pick out which brand they use.
