In this case, maximum utilization means maximum economic output, which is good for GDP and good for the country. It may not be the best for the local society, though. That part is hard to quantify and controversial.
If you have the capital, sitting on low value property can make you a lot of money.
Also, if you are a real estate investor, you can "launder" your profits to avoid taxes. That's why old shopping plazas will degrade until there is only a kung-fu place and a dollar store. It literally has a value sopping up real profits from thriving holdings with paper losses.
Under a system of pure land value taxes, an empty lot downtown would be taxed at the same rate as the highrise next to it, and taxed much higher than an empty lot in the outskirts—a huge incentive to put that empty lot to more productive use.
The proliferation of parking lots is a regulatory/zoning issue.
As old Marx put it, a commodity has two values. A use value, and a exchange value.
In the case of land, usage would mean building on it, farming it, or some such activity.
But even if nothing like that happens, the exchange value remains. Meaning that someone out there is willing to trade you for it.
In a discussion about problems with urban property in the US, an HN thread would decry property tax and wax on about land value tax.