If you use your business name in your day-to-day business operation like promotions, product labels, visiting cards , invoices etc, you are already protected to some degree. This is however true only if you are the only business using that name for your class of goods or services. This may involve a small geographical area. However, this way you cannot sue another business using your name. Getting that mark registered, bolsters your claim to that business name and further ensures that other businesses can not copy your name and/or defraud your customers.