This is tricky. Almost everyone accepts that the guys name will be used, but when it's questioned it's hard to come up with a good response: because everyone else does it or because that's the way it's always been done is the best I can come up with. I was lucky and my wife took my name and my kids have my name. It just feels right because that's what everyone else does.
The same questioning can be done in reverse. Why does your wife feel this way? Does your wife think "unique" is cute? My son is in pre-school and when I go down the name list every kid has one first name and one last name. Do you want your kid to unnecessarily stick out? What is your kid going to say when some kid asks why they has two last names? Ummmm, because my mom wasn't willing to let go of her identity and my dad's a pushover? They sure won't have a cultural response to it like that's the way it's done in my country. It'll just be awkward. Don't make your kid awkward.
Sorry that was all ramble with nothing helpful. It's a hard question.