League city is a strategic admin position with many advantages if properly utilized. 
League city gives league mates another resupply point. We can donate our resources to League City using commercial center. Quartermaster department can transport resources, supplies and armaments to league mates' cities or other league cities in need. League City also can use "Air supply" to recover all ground troops that need supplies in Admin Area. 
We can also covert city we don't want to League City. Then 4 leadership points will be back to us and this city is still belong to our league. 
We can produce advanced armaments in munition factory of league city.