Sounds like buzzword chatter.
If you're already doing EDI, then you are exchanging documents in a mutually agreed upon, standard format. So what would be the benefit of reformatting the existing documents in XML? (Which is what you asked, isn't it...) None, really, unless there's a bigger picture that we don't see, such as a merger with another company that wreaks havoc on all your enterprise processes. (I.e., a huge forced integration task.)
Your best bet might be, instead of trying to identify the benefits yourself, asking the chatterers what benefits they're expecting and why. If they don't have a solid answer, it has all been BS.