Nice to look at, for some people. Many couldn't care less. Of course, it's subjective. Bitcoins have value for some because those people value bitcoins over other things, like US dollars. It's a subjective value judgment why anyone trades one thing (dollars) for anything else (stamps, bitcoins, diamonds).

Stamps are only nice to look at for some people. The only reason I would buy a stamp would be to sell on again at an expected profit later on.

The value today comes from the expectation of future value, based on something as subjective as the opinions of a subset of society.

You can avoid taxes, tracking, and buy drugs with it.