It makes large scale collaborative performance possible through a browser - something that many people have at home, in their bag, or carry in their pocket. If you would like a more concrete example, or are from the Olympic committee, please take a look here: How this might be used.
NIME 2011 Workshop Presentation
Associated files for the Workshop presentation above:
SEAMUS 2011 Presentation
This presentation covers the thought behind using rails to distribute interfaces to participants, and some of the details of that proceedure.
Take a look at some thoughts here. . .