I am going to hazard a guess as nobody else responded. They have a lot of different tools for different aspects (animation,mocap,shaders,texture painting, model

I am going to hazard a guess as nobody else responded. They have a lot of different tools for different aspects (animation,mocap,shaders,texture painting, modelling, rigging, final render etc) and a USD allows them to quickly back-and-forth between the different stages on as-yet incomplete scenes to preview final renders, make fine adjustments further up and down the pipeline to accomodate for changes made elsewhere.