Pricing models allow a company to price products dynamically or on a common basis.
For example, airlines constantly vary the price of tickets based on the number of seats available on a given flight, the number of days before the travel day, time of day for the flight, projections of demand, etc. This is an example of a dynamic pricing model.
If a company has a high number of products to price, a pricing model can be constructed so that products with certain characteristics are priced at a constant markup over costs. This allows prices to both fully reflect costs and to get higher or lower margins depending on the class of product, differing price elasticities, etc. This is an example of a pricing model that prices on a common basis.
Pricing models allow companies to maximize revenue and profitability.