Why, indeed.
Putting aside the answer that the buyer paid that amount because otherwise it would have gone to **1 for $87, I can offer two explanations as to why a buyer would pay a figure which your question seemingly postulates is excessive:
1. Some people like to collect old tools simply for the pride of ownership and with no realistic expectation that they will ever us them, but because thay have the money and it gives them enjoyment to spend it this way. In that circumstance what one pays is driven by the market, and bears no resemblance to the economic value of the tool , say as a resource on which one may recover the investment by charging for its use. After all, you could as easiuly ask: what "sense" does it make to pay $1M for a used car.
2. Others ( including the writer) hold a belief that some of the older tools are simply superior to what can be bought that is made today. As a way of an example I was "raised" in vocational public education on Buck Brothers chisels that were probably early 20th Century product. Later, when I matured enough in my skills to be able to tell that father's Stanleys with plastic handles - and that had been used to open paint cans - limited what I could accomplish, I took to buying a few Buck Brothers of that day, ca 1960. As I recall they were about $25 in 1965 dollars; 1/100 of a new Mustang convertible. The steel in them was a disappointment, and this was confirmed when I would occassionally borrow a "real" Buck Brothers chisel from someone in the shop who apprenticed before the War and as a result had a set of the real McCoy; but I still could not afford to have my own. Now the time has come when I can afford an antique Buck Brothers chisel, and I buy them from time to time to build up a set. I choose to believe they give me an ability to do woodwork superior to the newest products. I expect that there are others that simply value the qualities of older tools.
Karl