From the perspective of the state, one of the benefits of growing larger geographically is that bigness makes it more difficult for residents to emigrate or cross over borders to escape taxes. Larger states are more effective at limiting options for relocation, and placing greater barriers in the way of residents who might be looking to change the the conditions under which they live. Even if we agreed that states can provide certain amenities of value, state powers still become dangerously prone to abuse the larger the state grows.