No but it is a question of personal requirements! If the lower prices and high mechanical strength are of major importance, then you may have good results with such wires too. There will be a slightly lower efficiency caused by the higher resistances in ohms. But this is practically out of consideration. The SW Broadcast-stations are using stranded bronze wires and are doing a good job: this wire has a resistance higher than the same in copper. Aluminium-wires are low-priced by mass production for electric fences. Ok for antennas, but stiff and breaks easily. Advantage: Lightweight! there are copper plated steel-wires on the market: very good and better than normal steel wires!