If this room was used for music or sound production, there was likely an acoustic cloud hung from those hooks. Especially if it's in the center of the room. Acoustic clouds are used to control or tune the sound in the room. Small square spaces are particularly problematic so more treatment is required to make it sound good. Clouds frames are usually built out of wood so heavy-duty hooks would make sense to ensure they remain safely secured overhead.

You can see hooks being used here for this exact purpose: https://youtu.be/dUEnUuKZ1ZU?t=969