Why is alumina dissolved in molten cryolite during aluminum smelting?

In the Hall-Héroult process, alumina is dissolved in molten cryolite to facilitate the electrolytic production of aluminum.12

Alumina (aluminum oxide) has an extremely high melting point of approximately 2,050 °C (3,700 °F), making it impractical to electrolyze in its pure form. By dissolving alumina in a molten bath of cryolite, the mixture can be maintained in a liquid state at a much lower operating temperature—typically around 950 °C (1,750 °F)—which allows for the efficient passage of direct current to extract the metal.31