One big advantage of iron is that you can forge it. Bronze has to be cast or cold worked (with annealing steps as necessary). You can't forge weld bronze either

One big advantage of iron is that you can forge it. Bronze has to be cast or cold worked (with annealing steps as necessary). You can't forge weld bronze either, so you need to braze/solder parts together. A skilled blacksmith can forge things from iron quickly and with little waste. It's especially important for things like nails and arrowheads that are needed in mass quantities.