What is SEO and why is it Important?
SEO is an abbreviation of Search Engine Optimisation and it's the process of optimising your website and content so it appears higher up the the search engines, such as Google.
The main differentiator between SEO and paid search advertising (like Google Ads), is that SEO is all about organic ranking, which means you 'earn' your position in the SERPs (Search Engine Results Pages), rather than 'buy' your way to the top.
Acorns or Mushrooms?
Think of Organic SEO as Acorns, and Paid Search as Mushrooms. Acorns take a longer time to grow, but they grow into a very solid Oak tree that's around for a very long time. Mushrooms, on the other hand, grown incredibly quickly, but soon disappear. Unlike organic SEO, where your position in the SERPs is earned, paid search advertising will literally vanish from the SERPs when your budget runs out - and keeping your paid search advert(s) at the top can be very expensive!
If you rely exclusively on paid search, you will literally vanish from the search engines when your budget runs out. Acorns, not Mushrooms is surely the better way to go here.
Where paid search can prove effective, however, is when you need to react quickly to market conditions or need to get a message out fast. You can 'buy' your spot in the SERPs - like turning on a tap, but again, this can be very expensive and the tap will eventually run out of water.
Perhaps a sensible strategy here would be to use a well planned mix of both organic SEO and paid search advertising. Unless you're not planning for your business or products to be around for long, the majority of your effort should be put into achieving a high ranking in the SERPs, therefore the majority of your budget should go into organic SEO.