One language for all, one currency for all. The alternative was "Euro" against "USD" but Europeans f**ked it up with Greece crisis. (and spain will be following probably)
And China? China is in another world dude. No one would want to go there. So basically China is worthless to most people.
Euro could never provide a strong fight against dollar, despite of whatever capital strength they possess because it takes social and political capabilities to back a strong currency, not just missiles. Spain is not going to end like Greece anytime soon, they've made the most recovery from their crisis in the whole euro zone circle. Also, China is not worthless, the whole world relies on it for manufacturing their products and provide the cheapest human resources.
That recovery is a bubbled one. It's based on precarious labor, low quality and temporal jobs that pay next to peanuts. The spaniards are holding without riots because they are living off under the table work and off grandparent's welfare. You are deluded if you think its getting any better for them.
My family lives in Spain and they told me everything which happens there, I am more informed about the place than you are. I can assume you don't live there because you're one of those people who reads a conspiracy theory over the internet and totally believes it. I'm anything but deluded, Spain might not be completely recovery free but they are doing so much better than what I think they would be like.