Hi
Well first thing any part of
SEO for a website is important.
When thinking of rankings you want to incorporate as many of the
SEO methods that you can.
I typically explain to clients if the site at #1 has completed 80% of the
SEO methods... then in order to surpass them... you would need to complete at least 81% of the
SEO steps.
On the flip side.... organic rankings are not always the best for traditional e-comm merchants.....
Hope it helps
Peace!