Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?

The standard free energy of formation (ΔfG∘) of Cu2S is greater than those of CS2 and H2S. So, Cu2S (pyrites) cannot be reduced by carbon or hydrogen.2Cu2S+C⟶4Cu+CS2 (Not feasible)   Cu2S+H2⟶2Cu+H2S (Not feasible) However, the ΔfG∘ of copper oxide is less than that of CO2. Therefore, the sulphide ore is first converted to oxide by roasting and then reduced.2Cu2S+3O2→Roasting 2Cu2O+2SO22Cu2O+C→Heat 4Cu+CO2[ Feasible ]