Since DBDOC shows you all the data used in your graphics, it allows you to see the taglists in parallel with the Composer and WinCAD ones. This makes the task of keeping the databases synchronized easy.
DBDOC shows you tags that are referenced by tag index only - a very worrisome situation.
DBDOC cross-checks the trend database entry with its related tag.
DBDOC tells you about the tags in your database that are not in any graphic, about tags that no longer exist in the database and tags that no longer have source blocks in the configuration. This information allows you to keep your graphics very tidy.
DBDOC gives you a direct link from the Conductor VMS graphic to the configuration CLD / CAD files, making fault-finding trivial.