Liquidity is a very good point. I'd also include another issue which I don't have a word for, because economics is not my field. That's the issue of permanence

Liquidity is a very good point. I'd also include another issue which I don't have a word for, because economics is not my field. That's the issue of permanence and authenticity, the value of knowing that the object you are looking at is in fact the same as it was when originally created, and not a reproduction or altered version. I collect first editions and other vintage copies of magazines I admire. Among my collection is a Vanity Fair from 1935 containing the obituary of Lawrence of Arabia, a story on the new Bay Bridge in SF, the "Brown Bomber" Joe Louis, and pleas for peace in Europe. I would not pay anything for a PDF of this magazine. As a physical artifact, it was worth the $30 I paid for it. There is utility and value in physicality that cannot be found in digital ephemera.