Some people might also enjoy both for different reasons. They could read the light novel first to get a full understanding of the story and then read the manga to see how the artist has interpreted it visually. This way, they can get the best of both worlds - the depth of the novel and the visual appeal of the manga.
However, if you enjoy a more detailed and in - depth exploration of the story, including characters' thoughts and more elaborate world - building, the light novel could be the superior choice. The light novel allows you to use your own imagination more fully when it comes to the appearance of things. For instance, you can create your own mental images of the apothecary's laboratory based on the detailed descriptions in the novel.
It depends on personal preference. If you like visual storytelling and seeing the characters and settings come to life right away, the manga might be better for you.