That depends on "when"....
In the early stages of a "Free" society they are essential....ownership of property and the right to hold property are tantamount to real liberty whilst the available property is essentially unlimited...
But what happens when (for instance) the population has grown by a factor of ten, but the available Real estate has remained constant? What kind of "freedom" will additional individuals be able to enjoy if ALL the available land is already the property of others?
You are entitled ONLY to life, liberty and the PURSUIT of property....there is no inherent human right of property ownership implied in the Constitution, in Natural Law, nor in Common sense!

