Well there’s an argument that the Royal family is an archaism, and not relevant to modern Britain, so yes, showing the Royal family still has relevance and is involved in things people care about now, is important.
But that does run the risk of looking like you are chasing the cool/fame of celebrities. Balancing act, I think William was right to do this. (I still think it was a massive mistake for him not to go to Australia for the women’s world cup final.)