The imagery of each of the words is significantly different. "Newhouse" inspires the image of what it says on the tin, a new house.

Casanova inspires the image of a castle (Casa), and maybe something new ("nova") or even a supernova. It's also likely that most English language people know at least one "Jacob," so the name has baggage with past associations versus "Giacomo."

True. But also doesn’t have any of the cultural legacy that presumably impacts how you hear the name…