I dislike Quora's decision to hide answers behind a login, which makes me go to the site infrequently. That said, Robert Frost, engineer/instructor at NASA, answered this question perfectly:
Why do some intelligent people care to remember and understand a massive amount of details (characters, relations, interactions, events) of completely imaginary and excessively detailed settings?
Life is short. It should be full of joy. Imaginary worlds are fantastical and thus more interesting than the real world. That brings joy.
No one has ever filled up their brain. There is room for the real and the imaginary. Being able to name every episode of Star Trek did not at all prevent me from getting my university diplomas or certifying as a Guidance, Navigation, Control, and Propulsion expert. In fact it helped. It gave me a place of happiness to go to when the mundanity of engineering wore me down.
Humans are hardwired to appreciate stories and patterns.
A life devoted to only the practical sounds like a miserable life.