A brand identity is essentially an identity which portrays your business - think of a person. When you look at somebody, quite often we have a tendency to judge people, from what they're wearing, to how they style their hair etc. This is nothing new. So when it comes to businesses, why is it any different?
Take a food retailer as an example, a food retailer with a strong identity comes across with the aura of professionalism, experience and safety. With food hygiene being a big factor in food production, a strong identity shows that the business doesn't cut corners and therefore you would expect that they wouldn't cut corners with your food. This could mean a logo, font choice, the way images are taken and the colours.
It's so important for a business to have a strong identity to attract new business, through safety, aesthetics and trust.