A human sees a heading, a price and a star rating. A machine sees text. Structured data says: this is a Product, its price is this, it is sold by this Organization at this address. Search engines use it for rich results, and answer engines use it to be sure who a business is.
The common types for a business site are Organization, LocalBusiness, Service, Product, FAQPage, Article and BreadcrumbList. In our benchmarks of Ghanaian industries, between 47% and 63% of sites carried none at all. Our free schema generator produces the main types as you type.