In 2012, Google launched the data highlighter tool to give less technical webmasters a way to communicate markup of a page or group of pages in a visual way. It is a pretty creative way to communicate schema and markup to Google for those unable to add schema to their source code.
But is that the best way to do this? John Mueller of Google says if you can and you can get into the code, using on-page markup is the preferred way. Why? Because code is more flexible, you have more control and finer detail.
Here is John's tweet:
I'd prefer on-page markup over data-highlighter -- it's fully under your control & easier to fine-tune.
— John ☆.o(≧▽≦)o.☆ (@JohnMu) August 17, 2017
I played with the tool just now and it is somewhat finicky to select the right piece of information. It takes time sometimes to select the right portion of the information and sometimes your date formats don't work with Google. Doing it in the code, which is what we do here, is way easier for me.
For more details on this tool see this help doc.
I should end by saying both methods technically work, but one method is more exact.
Forum discussion at Twitter.
