Making use of concepts shared with other standards setters reduces the burden for preparers and analysts.
It does require collaboration between participating standards setters but at a fairly minimal level compared to more fully fledged sharing as each standards setter can put their own labels and references on the underlying concepts rather than having to agree one set of labels and references between standards setters.
Example
Two different taxonomies can share a common energy module (listing the various types of energy, total energy consumed etc.)
Each taxonomy (one made by ACME, the other by XYZZY) contains references to its own official standards but not each others. A fact reported against TotalEnergyConsumed in the ACME taxonomy is comparable against a fact reported against TotalEnergyConsumed in the XYZZY taxonomy because both taxonomies are using the same XBRL concept TotalEnergyConsumed.
One taxonomy using sus-energy:TotalEnergyConsumed contains references to the ACME standard:
Another taxonomy using sus-energy:TotalEnergyConsumed (the same concept) contains references to XYZZY:
