There are many reasons for a business valuation - mergers, acquisitions, shareholders disputes, exits, succession planning, estate, divorce, insurance, financing..
If an owner is thinking of selling their business, or a percentage of ownership - understanding the business value and value drivers can help owners in smarter negotiations to get the best price and terms for their business. The earlier this process is started the more time the owner has to implement measures to increase the valuation.
Even if a sale is not "in the works", understanding the financial worth and value drivers is also good practice. Your business is a living entity, understanding what can add value or what is destroying value, whether external or internal will help management to understand the business on a deeper level, how they stack up in the market place, and what they can do to potentially improve the business.