Yes, you are correct and thanks a lot for replying. But consider this scenario:
I have a feature service which has 3 feature layers in it, a point feature layer, a polyline feature layer and a polygon feature layer. If I am making a user application on WPF, I donot think that it will be a good user experience for the user when he sees three sub feature layers instead of one in his/her application and then they have to add all these feature layers one by one to see the whole feature service.
Thanks