With decentralization we transfer the authority of production from a central organization to local entities. It is the process of redistributing power away from central locations.
With regards to politics, Alexis de Tocqueville maintained that:
Decentralization has, not only an administrative value, but also a civic dimension, since it increases the opportunities for citizens to take interest in public affairs; it makes them get accustomed to using freedom. And from the accumulation of these local, active, persnickety freedoms, is born the most efficient counterweight against the claims of the central government, even if it were supported by an impersonal, collective will.
We could decentralize the production of law and order, the power of energy production, the power of governmental systems etc.
Sustainable energy, like solar, decentralizes energy production. Would it not be great if everyone could produce their own energy?
Seasteading decentralizes governmental systems. Would it not be great if everyone could freely move to societies or communities with governmental systems they prefer?
Cryptocurrency decentralizes money production. Would it not be great if you could freely choose to use currencies that you prefer, instead of being forced by governments to use theirs?