Pre-iPhone 15, the Pro models used stainless steel for the frame. Not sure exactly why they ditched it, but it did have a reputation for collecting fingerprints.

The weight difference in the hand between the 14 pro in stainless and the 15 pro in titanium is considerable, I use both every day. Sometimes weight is a way to denote solid and premium like in watches, but with the size of phones and how we use them, being lightweight is really where it’s at.