I manage a small WordPress site for an educational non-profit in California. Looks like 30% of our traffic is coming from out of the United States.
It would help if this plugin only allowed traffic from within the US. Of course if I was in UK, I'd probably prefer that limit.
BTW, I selected all the countries and tried to CTL click one and the selection wouldn't change i.e. remove.
Also, allowing only one country would exclude the 'unknown' country codes, which are most likely the smartest hackers