Does that not prove his point? There is no functional requirement for gold in jewelry now that so many cheap stainless alloys exist. Why not make jewelry out of plastic?

The answer is: we, as a species, value gold far beyond its usefulness as a metal.

Do you remember the article posted earlier this year about how DeBeers literally invented the market for diamonds out of thin air? Before their campaign, diamonds were relatively cheap and not considered to be that special.

Like the dollar, or Euro, or gold, or even Bitcoin, the value of something is set by those who desire it.

Well, some people appreciates jewelry because of the rare materials, some other people appreciates "difficult" numbers (like big prime numbers, a more accurate pi, or in this case hashes that starts with many 0's) :)