Textured interior walls have a practical function, since the texture hides the signs of drywall installation – that is, the taped seams where the sheets of drywall meet – and other imperfections. It’s cheap and fast.
That’s why you often see textured walls in rental or commercial buildings. It’s also a more durable surface than a smooth wall, and less affected by minor wear and tear. And some people still feel texture adds character: The bumps reflect light and create shadows, making ordinary walls less “boring.”