SEO stands for Search Engine Optimisation, search engines discriminate against ID numbers in URL strings and this mod helps and makes life a little easier for those lovable bots and spiders who crawl our pages.
Whether you believe the fact that search engines discriminate against ID numbers in URL strings or not, the fact of the matter is that
[1]
http://www.theshisha.com/shopcart/product.php?productid=16242
will never look as nice to the end user, or search engines, as
[2]
http://www.theshisha.com/shopcart/Soex-Herbal-Strawberry-250g-pr-16242.html
With the second option, you can see what the product is in the URL without even going to that page, where as the first option you do not know what the product is.
Both these above links, link to the same page but the search engine, spider that crawls our web sites would prefer the second option which is a html page and not a PHP page.