My husband's family still has this tradition. I know many, many Italian families that still do this. All of the first-generation Italian families I know including my own family take part in the tradition.
There's no registry, It's just a big, fun party introducing both sides of the family to each other officially. Many or most of the guests bring engagement gifts which they would have sent to the engaged couple anyway. These are people who would also attend the wedding and may or may not attend the big bridal shower (as opposed to the personal shower that includes only the bridal party).
I should also add that we're not wealthy or well to do. The parties are always during the summer when we can have these parties outside so that they're casual. They're BBQ and partially catered so that there's a ton of food, and being Italian many of the guests bring some food to contribute. It's just an excuse for family to get together and celebrate.