Why are the oxidation and reduction half-reactions separated in an electrochemical cell?

In an electrochemical cell, oxidation and reduction half-reactions are separated to facilitate the flow of electrons through an external circuit, allowing for useful work to be performed. This separation ensures that the oxidation reaction occurs at the anode and the reduction reaction occurs at the cathode, maintaining a clear pathway for electron transfer. Additionally, this separation helps to prevent the immediate recombination of oxidized and reduced species, which would otherwise diminish the cell's efficiency and energy output.