Yeah, I have used the chain. Not that you should care in any way, but I still do not agree with the approach.
In you new docs you are suggesting a work around, are you not? I am talking about using service activator. For me service activator has a very distinct endpoint-like nature, while Filter and Transformation have a translator-like nature. The difference is small, but when I need transformation I would naturally try to use translator rather than endpoint.
When I see configuration for service activator, I expect it to connect me to some messaging system, I guess. But yeah, maybe it is just me .