The US is allergic to it, but needs to get over it.

Aluminum wire was tried in the 1970s due to a spike in copper prices. The problem was that they just tried to swap it right in. Aluminum and copper have different rates of expansion. Over time, that would slowly loosen the connectors, and the wires would pop right out and cause a fire.

You can design connectors to handle both, and you’ll see many electrical things today specify that they’re good for aluminum or copper wire. It still has a bad reputation among electricians; they haven’t unlearned the problem yet.

Now, one place it’s more of a problem is in things like transformer windings. There are kilometers of wiring in any of them, so the higher resistance of aluminum is a problem.