[1] Whilst it is possible to manually write a computer program to achieve this, XML data binding tools generate the source code to perform these tasks.
Specifically, information such as comments, XML entity references, and sibling order may not be preserved in the object representation created by the binding application.
Furthermore, XPath allows the application to bind the relevant data items and filter out everything else, avoiding the unnecessary processing that would be required to completely unmarshall the entire XML document.
One of XML data binding's strengths is the ability to deserialize objects across programs, languages, and platforms.
[2] You can dump a time series of structured objects from a datalogger written in C (programming language) on an embedded processor, bring it across the network to process in Perl and finally visualize in Octave.