Google HTML/CSS Style Guide - Optional Tags

Optional tags? Is this the way to write HTML after you get experienced? They call for dropping the head, body and html tags altogether if there isn’t anything in there. It seems the also says it’s ok. Is there any real world situation where this would be the case? Google’s own “How our business works” page is loaded with div, section, p, etc. Where could you drop “optional tags” and save any meaningful scannability or file size?


I have read through most of the documentation, those optional are to optimise loading time of your site, as the bigger your files are the more time it will take to load. So for big HTML files those can be used, but while developing you should avoid those specifications as it might make it harder to code. And in most cases your file can’t be that big to cause an issue so not using them isn’t a problem, but when loading time is an issue use them to decrease loading time.
Using those from start may bring confusion, as to where something has ended, where the body starts, where does the p tag ends where does the head start and end etc.
So use those specifications when and only when you have fully developed the web page.
Though I’ll suggest against using it as in most cases your web page can’t get that big to need optimisation.
Though it’s a usefull thing to know about.