This explains why the price per unit is very high, but the land itself is valuable in the first place because there's high demand for it and that land would be

This explains why the price per unit is very high, but the land itself is valuable in the first place because there's high demand for it and that land would be even more valuable if it were legal to build more units on it, which would lower the price per unit, but increase the overall value of the investment. This is what's called a win-win.