A useful utility for SOAP::Deserializer is for parsing raw XML documents or fragments into a SOAP::SOM object. SOAP::Lite developers use this technique to write unit tests for the SOAP::Lite module itself. It is a lot more efficient for testing aspects of the toolkit than generating client calls over the network. This is a perfect way for developers to write unit tests for their custom data types for example.
Here is an example of how raw XML content can be parsed into a SOAP::SOM object by using SOAP::Deserializer:
$xml = <<END_XML;
my $som = SOAP::Deserializer->deserialize($xml);