Another attribute of small is beautiful: (what we call) democracy.
The idea of democracy is to take the citizens’ location as fixed, and the identity of those in government as variable, the “representatives” matching the preferences of the people. But you can get similar results of representation, even under dictatorships, by varying the people’s location instead.
You are free to move to the canton or municipality where you feel the dictators represent your tastes & beliefs, and such competition puts pressure on local municipal dictators to please taxpaying constituents so they stick around.
So the smaller the size of political units (and the larger their number), the more democracy we get in the system.