The power in Iceland to do this is so cheap that it is economical for companies like Alcoa and Alcan to ship the raw materials all the way to Iceland and then ship the final product out it to its customers.
That said, if the process really can be made to work, CO2 would go from being a polluting waste product to a valuable raw material, and it might even become worthwhile building systems to capture it and pipelines to ship it around.