I'm not a Harry Potter fan but I still got something out of visiting these studios. Firstly how much effort goes into making films of the scale of the Harry Potter films, how many people are involved, the talents required to create the visuals and the sounds. A useful counterpoint to the instant gratification of our day, where eveything is a swipe away, where everything is superficial and cheaply obtained.
Secondly how for those working on these films how they become part of a team a second family of those working - an experience I envy. Perhaps a reason readers become so enmeshed in the Harry Potter books is that they identify with Harry Potter not only in his becoming wizarding superstar royalty but also that he finds a real true family to belong to.
Thirdly how rich the world that J K Rowling has composited is, plenty of material for people's imaginations to roam in. Like all authors and authoresses she has borrowed heavily from others, cooking up her books from off the shelf ingredients.