Let's start with a metaphorical cliché. With no map the traveller is likely to wander off track. As you ask your colleagues and customers to travel with you towards your vision, a brand strategy is that map.
For this reason, I would suggest that the brand strategy is one of the most important documents your business could produce.
Don't have one? Let me try and convince you to take steps to get one.
What a brand strategy is not.
Firstly let's be clear. A brand strategy is not a business or marketing strategy. A business strategy is a high level plan for reaching specific business goals. These are typically growth goals. A marketing strategy is usually a response to a business strategy, in how marketing will be used to reach those goals. These strategies are typically set out or reaffirmed on a year by year basis with details of regular activities, marketing channels, metrics and budgets. Business and marketing strategies are temporary. They are full of facts and figures. They are full of pie-charts and tables. They put the business first, not the customer. Most people in your company will never read them or ever want to read them.