Uses for small parcels of land

You would usually be right, except that's not the case in this example. These properties have already been delinquent for at least 4 years. You can read the description here:
slco.org/auditor/tax-sale/

and the bit about tax liens here:
slco.org/auditor/tax-sale/faq/

You could start a solar panel farm and sell the power to the government.