I think paid advertising can't give you more business because user generally clicks on website or results coming through on top position by organic search. People rely on them and you can get more business leads through organic search. So search engine optimization is very important to increase website traffic.

Yup you got that no doubt paid advertising is a good but SEO is way more important to make you getting good traffic from search engine and getting good traffic means the chances of getting conversion would be much more higher !