So, you've hired an SEO expert to help you increase your website's ranking in the search engines. It seems that all she's doing is working with Google. You're wondering why, and at the same time wondering if you could have done all this yourself.
Your SEO expert is working with Google for good reason. Google is the largest and most used search engine, and offers website owners all the tools they need to ensure a high ranking. (By the way, she's working with other engines, too.) By following Google's requirements to the letter, your SEO expert can help you rank much higher in the search engines. However, for this to work, she has to follow their specifications exactly, including providing them with site maps and robot.txt files. She's not taking the easy way out; working with Google and the other search engines is critical if you want to rank high in their searches.
To answer your other question, "Could I have just worked with Google myself and saved money?" Well, the answer there is "Maybe yes, but probably no."
In theory, the answer is yes. Google and other search engines would be willing to supply you with all the tools your SEO expert is using.
But, in practicality, the answer is no. Your SEO expert has done this dozens of times before and can get it done while you're reading the manual. And, she'll get it done right the first time, while you'd probably have to redo parts a few times to get it right. After all, do you even know what a robot.txt file is?
Don't sweat the investment you're making by hiring an SEO expert. The work they do is work that would be very labor intensive for you. Their work will provide you with years of results in bringing visitors to your site. Keep being the expert in your field and let your SEO specialist be the expert in hers. If you don't have an SEO expert, but want to find one, visit http://www.localseoservices.net/