Then there is no point of using dataTransfer objects to optimize client/server interaction if using DCOM?

I got the idea of using such an object from Martin Fowler's "Patterns of Enterprise Application Architecture" book where he suggests using datatransfer object to send data from different sources (e.g tables) over the wire with just one remote call.

Short description of this is available:
http://www.martinfowler.com/eaaCatalog/dataTransferObject.html