Because you should never pass up the opportunity to learn something!
The magical world of J. K. Rowling is known by millions (if not billions) of children, teens, and adults. Especially those who grew up reading the books and then watched the magic come to life of the silver screen later on. J.K. Rowling created the world of Harry Potter from her vast imagination (and personal experience) and perhaps from other sources. These included Dickens and Tolkien, which she says filled her free time during her college years.
J. K Rowling attended University of Exeter and received her BA in French and Classics. It is evident that she received a degree in Classics, because the Harry Potter series is filled with Latin words and ancient mythology. While the mythological references may be easier to see in character names (i.e Minerva McGonagall as in Minerva the Roman goddess of wisdom); the Latin reference may not be as discernible.