There are "boyfriend pillows" [0] that partially fulfil the feeling of being cuddled/held by a boyfriend. They sell well, apparently.
I imagine that if you could do the same for a "boyfriend hand-holder" product that partially fulfils the feeling of having your hand held, it would also sell well.
If this happened, no-one would say that the product had no value. Yet the product is only capturing part of the value of actually having a boyfriend hold your hand.
Therefore I would say that you definitely have created value by holding your girlfriend's hand.
Try asking your girlfriend whether she thinks holding her hand is worthless :-) Making someone happy (-ier) is a great, canonical example of creating value.
People will tolerate surprising levels of discomfort, even financial loss, to be physically close with other people.
I'd say this basic need goes even further than humans. Certainly at least mammals, with their complex endocrinological and social systems; but possibly any organism that procreates via sex.
I'm told some people pay prostitutes to just hang out with them to feel some sense of intimacy, without even having sex. Ie, people are basically being paid to hold hands.
