In marketing, the customer comes first. You cant market to potential customers unless you understand their wants, needs, desires, state of mind, interests, income, and more. So why do you think it is important for a marketer to understand how a customer makes that final purchasing decision?
If you were purchasing a car, which one of the following factors would most influence your decision to buy? Then lets flip, it If a marketer knew this about you, how could he/she use this to better market a new car to you?

Price (or)
Color (or)
Style (or)
Status (or)