I don't use any of that stuff but do use the "Rich Snippets
" microformat, which is widely regarded as useful.
To quote Google "Including structured data markup in web content helps Google algorithms better index and understand the content. Some data can also be used to create and display Rich Snippets within the search results."
In my case the Rich Snippets micro data is primarily added at theme level and in the case of images with string replacement on post serving if the itemprop="image" is missing.
A couple of reasons having support for this built right in might be better are as follows.
In the case of images auto including the itemprop on image insertion and saved with post (in much the same way alt="" should be added if that attribute is missing) would be more efficient.
Support at theme level would vary from theme to theme, if included at all(which may/may not be the better option).
If you want to see how this looks you can use the
Google Testing Tool
and select fetch URL using the following link