I don't think the purpose of this particular use of XML is to make it meaningful. It is used as a method to transport data.
For the purposes of this demo, the author takes a clean approach and concisely shows how to accomplish the task. I would object to taking this approach in the real world, however.
It is a small point, but worthy of consideration IMHO: if the insert fails in such a way that the sproc aborts, you leave an open XML document with no handle available. If this happens enough times you will exhaust the "MEMTOLEAVE" area and be forced to restart your SQL server. I would load the XML into a temporary table, destroy the XML document, and then perform the insert, perhaps after validating the data.
This is a good article and it demonstrates a reasonable use of XML in the database.