I've been thinking along these lines. My last KH is on the county records at $400,000. Admittedly its in a spendy suburb of Seattle. But even half that times the number of halls in the country yields a big number. Also, that value would be carried on the Watchtowers books as a fixed asset, which is a number bankers love. The loans, which are some amount less than that are subject to a deduction for possible bad debt, making them less desirable to bankers. This could all be very important if they are obtaining bank loans to finance other projects.
The Watchtower's finances are some of the least transparent of any so-called charity.