Many sites have fast hosting, but come up slow because of external services or widgets, even images.

Javascript and buttons from external services can block the rest of the website design until they are downloaded by the visitor. The local stuff would have loaded fast as usual, but the way web browsers read web pages is top to bottom and in chunks or two or four elements at a time. So, if four of a site's first images come from an external website and they're slow, the site won't load until they do.

If there's any way to put the element after background design, it won't make the site look unresponsive when these elements won't download fast.

Anything from free analytics like Google Analytics to social media sharing tools can slow your site or make it completely unresponsive. If you bother investing in quality hosting to make your site fast, this is a terrible waste, and the fix is usually pretty simple, even if your site has something at the top that comes from off-site sources.

You can pload the local template content and lay this external content on top of it in a div of some kind. A little div CSS magic and your site loads as fast as your high end hosting service, and the free or outsourced widgets don't break your site.