Yes I agree and yes it is fair to give money to another state to build roads because it decrease power centralisation and promotes unity in action.
Explanation:
This directly relates to the system of checks and balances.
It is the system designed to reduce the effects of centralisation of power by ensuring that no single authority has complete control over decisions and promotes cooperation.
For Example: The tripartite system practiced in different countries where judicial, legislative and executive aspects of government has equal authorities in amending or removing the law.
In regard to projects like building roads other states can cooperate with one state to improve its infrastructure for equitable development.
