From RDFaWiki

Clickable Vocabulary Terms are Useful

For someone that is viewing your RDF vocabulary, being able to not only click on a link, but copy-paste a link to vocabulary terms is very helpful. In short, making RDFa authors lives easier should be a primary goal for RDF vocabulary authors.

Example

For an example of a direct reference to a vocabulary term, check out video:Movie.

Also note that you can click on vocabulary terms on the page and navigate to other vocabulary terms on remote pages.

Reasoning

You want to make it as easy as possible for RDFa authors to understand and use your vocabulary. Making it easier to navigate between vocabularies, instead of relying on them to open a new tab, enter the URL in by hand and perhaps navigate to the proper section will make their lives easier. Easing the burden on RDFa authors will pay off as the easier it is to use your vocabulary, the more pages will integrate it.