Use by reference
Groves allow any component(s) of any resource(s) expressed in any notation(s) (XML or non-XML) to be transcluded into any components of any resources expressed in any notations (XML or non-XML),
...without changing any of the resources involved.
Groves allow there to be a single authoritative copy of each datum, regardless of its notation.
Groves allow each datum to be expressed in the most cost-effective notation.