With XML , the GUI is extracted. Thus, changes to display do not require futzing with the data. Instead, a separate style sheet will specify a table display or a list display. Searching the data is easy and efficient. Search engines can simply parse the description-bearing tags rather than muddling in the data.
Tags provide the search engines with the intelligence they lack.
Complex relationships like trees and inheritance can be communicated. The code is much more legible to a person coming into the environment with no prior knowledge. XML is self-describing. All Rights Reserved.