It can sometimes be confusing for people to understand the differences between things that somehow look similar. Aluminum is known to be a type of metal while galvanized steel is usually created. This would require the steel to become dipped into another metal which is zinc. A lot of people may like aluminum when they want something that is durable enough but would remain to be lightweight.
This explains why this is one of the metals used in creating different furniture pieces and so much more. Galvanized steel is heavier than aluminum and items that are made out of galvanized steel will usually cost more money than aluminum.