This report lets you see where traffic originate (Continent, Sub Continent, Country, City). For web traffic, Location is derived from mapping IP addresses to geographic locations. City location may not be accurate for traffic from mobile devices.
From location, you can infer some cultural norms that might be a good influence on your site design and content. For example, if you sell a product that is equally viable in the Middle East and in Latin America (e.g., air conditioning, water coolers), you might develop a separate site for each region with different graphics and imagery.
Understanding location can also help you choose where to focus your advertising. You may want to advertise more heavily in areas from which you receive little traffic because you're certain your product is a good fit and those areas represent an untapped market. Or you may want to focus on areas from which you already receive a lot of traffic because there is a natural fit for your product.
You can use Segments to compare traffic such as New and Returning users per location, or All Sessions and Sessions with Transactions per location, and then see whether New York users return at a higher rate than London users, or whether there is a higher transaction rate in San Francisco than in New York.