say a government is selling a piece of land (or, "a society is using markets to allocate land efficiently")
compared to no tax, imposing a land-value tax would decrease the amount purchasers would be willing to pay
ie. reduce revenues to government at time of sale
BUT, it would provide revenues over time, correlated to the changing value of the land
b/c individuals and corporations are more short-term focused (than a government or society), the price they are willing to pay is much less than the true value to forever losing a piece of land
by taxing value over time, the government needs to worry less about "predicting" the true opportunity cost of the sale (or, is better able to capture the true value of the land)
similarly, the buyer has less immediate out-of-pocket expense, which reduces risk (though, at the cost of future-rise-of-value-thus-rise-of-tax risk)