The essence of a self governed, collaborative group of people forming an independency is (aside from joint rules and a constitution) to source services together.
Typically such services are very expensive and therefor it makes sense, to source them together, as a collaborative effort, where everyone contributes to the best of their abilities and that benefits all.
Services, like safety/security for its people, a joint healthcare systems, generation systems for education / retirement, social security systems, etc.
Find out more here: