Webizing the Javascript Object Notation

The language that the Semantic Web is based on is RDF, a simple language
consisting of binary property associations and just a few datatypes. But it's
often been said that RDF isn't enough to decently model some distinctions,
especially N-ary relationships that are a higher order than 2.

On the other hand, its power is that it uses URI as one of its datatypes,
allowing people to share information about data.

So what if JSON were modified to have a URI datatype? Would its utility be in
some ways greater than RDF, even if it were to be less formal in meaning? Does
all of the utility of using URIs as datatypes lie in independent meaning, or
are there other advantages too?