You're right about how it appears. As the API documentation says:
A convenience class to handle simple transformations. The JAXP TrAX classes have more bells and whistles and can be used with JDOMSource and JDOMResult for advanced uses. This class handles the common case and presents a simple interface.
(In case you didn't know, "JAXP" refers to the classes which are now standard in Java, in this case javax.xml.transform.Transformer.)