This is not just about money or a street vendor selling a few knockoffs. This is a major retailer in Great Britain that is, essentially, telling an artist to go to hell.
The copyright laws that allow this practice are out of date. I think Rihanna should be celebrated for going after this company based on the need to win some sort of control for artists. You could make the case that there are no winners here and that everyone is being greedy. Rihanna has spent a lot of her own money doing this; if it were to benefit a struggling artist in the future, then it would definitely be worth it.