Wouldn't your family still want to follow the same traditions whether your legal joining was called a marriage or a civil partnership, Fruit? I know a few gay couples who have had a traditional "marriage type" ceremony for their civil partnership, sometimes pushed for by their families! And heterosexual couples who married quietly in a registry office with no guests.
I do agree that marriage historically has a bad history of women being property, but surely CP is just renaming things, if the legal picture is the same?
Although I do agree with a pp who says that if this encourages couples to take advantage of the legal benefits of marriage then perhaps it should go ahead, even if it seems unnecessary in a legal sense.
I worry about friends who have given up/ scaled back their career to support their high earning partner, but he "doesn't believe in marriage" so they stay unmarried. Although in some cases I suspect he won't "believe in" CP either....