Regardless of the Bludit's flat file system, you'll always need caching in some form. So, what are some of the other benefits of caching?
You speed up your website for users – Thsi is the the primary advantage of this plugin. Since the website moves faster for users they are now more likely to browse around. Faster websites are known for decreasing bounce rates, since people are not interested in waiting around for a page to load for 10 seconds.
Your server uses fewer resources – Yes, even the Bludit uses low server resources, this plugin will help you even more, since the fewer resources make for a faster site.
You may see a boost in search engine optimization – Once again, this relates to the speed and user experience, but with all of those areas improving you're able to the search engines that your website is worth indexing at a higher ranking. Basically, a fast website = SEO improvement.
Download the plugin from here and install it. You can choose the duration of the cache and if you want to compress the html file(s). You can also clean the cache files at any time.