The use value of gold is just a little fraction of it's exchange value - so why people buy it? Because they expect someone else to buy it back from them.
Indirect exchange is
only one of multiple reasons people buy gold. There are many directly serviceable uses of gold and at least one of those reasons (ornamentation) were why people wanted to acquire gold
before it was ever used for indirect exchange.
Gold is used as ornamentation mostly *because* it is expensive. The technical uses of gold are tiny. Most of gold value is what you call indirect - and it relies on other people buying it back from you later. You can say that the tiny fraction of what you pay for gold is somehow backed by it's serviceable use - but what with the rest? In bitcoins you don't have that tiny fraction - only the rest, but in exchange it is more convenient as a medium of exchange, in the internet age, then gold. If you read the books you lectured me about - you'd found out that the reason gold was used as money was because it was a convenient medium of exchange.
Personally I don't like many of the bitcoin system solutions - but bitcoins are money.