Is there any particular reason why aluminum fittings are used as opposed to brass or steel? Just weight savings or something else?

 

You sometimes end up with a better seal with aluminum because it's a softer metal. The brass will usually start to oxidize pretty quick changing over to a pretty black/green color. Most of the time it's a visual thing.

Matt

 

It's true!! It's because they look pretty. With the proper use of teflon tape/paste you can seal anything up