Fiction and non-fiction are both a form of content, but their functionalities differ massively.
A work of fiction is great when I can’t stop turning its pages. Non-fiction is great when it compels me to stop, think, and maybe take action.
Time flies when reading a great fiction book; time stops when you are reading great non-fiction.
A well-written fiction gives you pleasure; well-thought-out non-fiction lends you new perspectives.
Great fiction hits you like a drug and makes you crave more dopamine hits. The entertainment value of fiction diminishes over time.
Great non-fiction hits you like a truck and leads you to new epiphanies. Its value doesn’t deplete as fast—you can come back to read it again and again.
Of course, these are not mutually exclusive; but I think it’s generally the norm.