Land value tax means you don’t pay any extra tax for developing your property, but you do pay extra tax if the neighborhoods get more expensive. Ergo, incentive for investment and disincentive for speculation.

Suppose you do a “buy and hold” strategy on a neighborhood that is gentrifying. The increased taxes you pay each your will eat into your profits. If you sell, the buyer will have have to pay those taxes too, so the value will be lower.