TFA explains that Japan is unusual as being the only country in Asia with two cities in the top 10 most liveable cities in the World. That's why they wrote the article. If Spain had been the only country in Europe with two cities in the top 10, they might have done it in Spain.
plus it's the BBC, plenty of UK-ians living in Spain. No need to highlight that when a solid chunk of the readership are in or will go to Hispania