Based upon your research address the following questions:
Complete testing of a web-based system before going live can help address issues before the system is revealed to the public. Issues such as the security of the web application, the basic functionality of the site, its accessibility to handicapped users and fully able users, its ability to adapt to the multitude of desktops, devices, and operating systems, as well as readiness for expected traffic and number of users and the ability to survive a massive spike in user traffic, both of which are related to load testing.
simulate virtual users which will repeat either recorded URLs or specified URL and allows the users to specify number of times or iterations that the virtual users will have to repeat the recorded URLs. By doing so, the tool is useful to check for bottleneck and performance leakage in the website or web application being tested.
finding bug, weak point and bottle necks in a web application
It didn't really change anything at this point. I have ran some applications through SEO testing to find improvments that need to be made.