Nice post..
SERP is "Search Engine Result Pages" means when you enter a query on search box of a search engine and click to search then as a result lots of pages come out related to search query...those are the SERP.
SERP is the amount of listings that you have in Google. Yes, having more SERP gets you more traffic IF and only IF you optimize the right keywords. Having a lot of SERP on the wrong keyword won't get you anywhere so optimize your keywords wisely. All the Best Bro.