issues with wsdl:endpoint@address

Issue 1: the spec and the schema is inconsistent. 
 
In the spec, address is an "optional" attribute of endpoint
 
 <endpoint
          name="xs:NCName" 
          binding="xs:QName"
          address="xs:anyURI"? >
      <documentation />?
      [ <feature /> | <property /> ]*
    </endpoint>

The address attribute is not defined in the schema @ http://www.w3.org/2004/08/wsdl/ <http://www.w3.org/2004/08/wsdl/> 
 
<xs:complexType name="EndpointType" mixed="false"> 
 <http://www.w3.org/2004/08/wsdl/#> - <xs:complexContent>
 <http://www.w3.org/2004/08/wsdl/#> - <xs:extension base="wsdl:ExtensibleDocumentedType">
 <http://www.w3.org/2004/08/wsdl/#> - <xs:choice minOccurs="0" maxOccurs="unbounded">
  <xs:element name="feature" type="wsdl:FeatureType" /> 
  <xs:element name="property" type="wsdl:PropertyType" /> 
  <xs:any namespace="##other" processContents="lax" minOccurs="1" maxOccurs="1" /> 
  </xs:choice>
  <xs:attribute name="name" type="xs:NCName" use="required" /> 
  <xs:attribute name="binding" type="xs:QName" use="required" /> 
  </xs:extension>
  </xs:complexContent>
</xs:complexType>
 
Issue2: why the address attribute is optional? The spec doesn't say anything about under what situation the address attribute may be left out. What's an endpoint without a network address?

Best Regards,
Kevin