I have a question if automated optimizing of HTML has any performance benefit ? I am using deflate on my Apache. My HTML is manually structured so it has a lot of whitespaces, so I thought if it would help to strip these whitespaces so the resulting HTML would be smaller.
Absolutely not. gzipping in the web server will take advantage of redundancies like spaces. Any processing performed to compress spaces in your html will simply duplicate that processing, and risk messing with any CDATA you have.