So why do websites make you do surveys? Put simply, people make money from you when you fill them out: it's called CPA advertising. This is where a website gets paid when you perform an action such as filling out a survey.
Are all online internet surveys bad then? No - you can make money by filling out online surveys: it is one of the simpliest ways to make quick cash online! Marketing is big business: by learning to target products at the right people, companies cut advertising spending and increase sales. Online surveys can therefore pay cash for your valuable opinions. It's just that this site doesn't believe that you should be exploited for the gain of others.