True. Anything rare and desirable (supply and demand) can have value, and that value can steadily increase, even though you'll need a specialty market to trade it or sell it.

eBay has really had a great impact on this. I collect vintage Star Wars figures. Before eBay, I would have to buy specialty books and magazines to determine their worth, then find a specialty store to sell them to. With eBay, you can buy and sell pretty much anything immediately. Even gold. Even bitcoin.