A trademark is a company's calling card. This applies not only to large and well-known companies but to smaller businesses as well. Your trademark allows others to recognize your products and services. Your trademark distinguishes you from others.
Complications can arise if others copy your trademark or if others use a trademark which can be confused with yours. Through a trademark registration, you can protect your brand/mark by restricting others from using its name or logo.
A strong trademark can also be of great value. In fact, the top 10 well-known trademarks in the world are worth billions of dollars. Any trademark is part of the company's assets no matter what degree of public recognition a trademark has. Trademarks can be transferred (sold) or given in pledge to a bank as part of your company's assets. You can grant a license to someone who wants to use your trademark. In short, your trademark is a marketable right that can have considerable value.