First of all Congratulations,

It's really great to know that you created an SEO friendly website and got the results within a week itself.
And Offcourse SEO is indeed an incredible marketing tool. SEO aka Search Engine Optimization which means optimizing the website in such a way that it attracts organic traffic and readership from leading search engines. I believe every business should invest time and money in search engine optimization.
Millions of people search for your product and but there are thousands of competitors as well. So how will you make sure that you'll rank first on the SERP rank 1st bagging all your competitors? Here's when SEO comes in role. It helps you to pull in the quality traffic. And it goes without saying that more and more organic traffic will also lead to increase in the sale and conversions. Not only this it also increases brand awareness, builds trust and loyalty of your business. And like it or not but it also influences the purchasing decision. And SEO proves to be extremely beneficial for start-ups and SMEs as it provides them competitive edge and helps to gain market share. I can mention a more about SEO because SEO is the topic on which whatever you learn is less.
And trust me if you don't own a SEO friendly blog then you are seriously committing a mistake.
If you have any doubt or query regarding SEO then feel free to ask me here. I would be an honor for me if I could assist you in anyway