Science-fiction space stations simulate gravity by rotating. The International Space Station doesn’t spin because it’s used for low-gravity research.
The International Space Station is a one-of-a-kind lab-oratory for a specific reason: microgravity. There is no other facility in existence that allows humans to conduct research in a sustained and stable microgravity environment where many disciplines, from material science to microbiology, encounter exciting new results.
Creating artificial gravity, which comes with a number of technical constraints, would eliminate this unique asset. Even the adverse effects astronauts experience while living in microgravity, like bone loss and muscle atrophy, help teach us about the fundamental mechanisms inside our bodies, which leads to benefits for those of us still down on Earth.