What do we value?
Is a vase really worth £43,000,000 and is a ten pound note really worth ten pounds?
Currency can be all sorts of things; long ago barter systems were in place to exchange goods. Some societies used salt as currency. We use paper for our 10 pound notes and metal for our coins.
Value is relative to the person who wants it, or needs it, if the Chinese wish to buy back an expensive vase they are paying for the heritage and history and all that the vase means to them. So therefore the vase becomes more than just a vase.
If you are considering the actual value of paper that the ten pound note is made from.... paper is very cheap and worth next to nothing. However if I had 10 pounds in my wallet- it would mean much more to me than the paper it was printed on.