Well, it is because you are passing into vRO variable "My_Deployment" = VCACCAFE:CatalogResource... So, you can play with this object what ever you want (like My_Deployment.setDescription(Bla-bla-bla) )...
But you (and me too) actually need a method/class/RESTAPI to update our original object, kind a transfer of properties from My_Deployment to already existing VCACCAFE:CatalogResource. Similar to "updateVCACEntity" method for vCAC objects.
