We may be attracted to different aspect of another human being :
their wealth to fulfill our material needs,
their sexual drive for satisfying our libido,
their beauty, youth and strength so we can brag about being attractive to this type of people,
their love to help us survive our humaine emotional weakness,
their intellect to open our minds.
You get the idea, so, of course, we can extend this list.
Seems extremely difficult task to connect everything, so they should start just connecting the blood vessels and not connect the nerves at first (or maybe do something else entirely … i see this is London, U.K., … well, they probably have some issues in health care and prevention … i do not know much).