I'll answer in a different way from others. Property taxes, in theory, ensure that the property within a jurisdiction is being used productively. Since you have to pay for the land no matter what, it's a good idea for you to do something with it that's productive. Even homes - it ensures that someone is loving theee and not just letting a house be empty.
In practice, that breaks down - speculation, tax writeoffs, taxes that haven't been adjusted in decades all mean that people/corporations don't give a shit and let property rot.