Yes subjective. Both types of value is subjective. That is why everyone should decide what they want for themselves in the market, and what they are willing to sacrifice to achieve it. If you already have some of that what you want, that will change your values, also your total situation, and not least, your personal preferences. If you like fresh vegetables, you might want to trade some of your time in a job, to somebody who wants the work done, in stead of growing the vegetables yourself. Nobody has the knowledge, nor the right, to decide for others. This is why voluntary action is best: more freedom (by definition), and more wealth for everybody.
If so, do you agree that we could say that gold value is
backed by its inherent
objective properties through an individual's
subjective valuation of them? If you don't like the word "backed" used here, what is, in your opinion, the best term describing the sustenance of value by objective properties?
Backed is a broad word, but in the realm of money it means that there is some entity that is willing and able to exchange the backed money for a specified amount of something else. So gold is unbacked.
I prefer to use direct use value. That value is not dependent of what others think (well if you want it, because others think it is pretty, but not yourself, that is in the fringe). Also in the realm of money, intrinsic value is the same as value for direct use, but that word has the same definition problem, because it is used for other things. By the way, I can not think of anything that have absolutely no direct use value, absolutely in the mathematical sense, after someone has selected it and brought it to the market.
Gold is unbacked, bitcoin is unbacked. In history there has been gold-backed banknotes. We have Casascius coins, but that is really the bitcoins itself hidden inside the coin. I think it is inevitable that bitcoin-backed notes will appear in the market, and I welcome it. Bitcoin would be excellent for backing.
If it remains for an individual to decide what property should be considered as valuable (subjective valuation), therefore any subjective value would
be direct use value (as you said before in respect to gold prettiness). If so, then, say, bitcoin security should by logical necessity be considered as direct use value too since there are many people who value bitcoin security high, right?