There was a desire to see what was sufficient to generate photorealism. Rendered jello, fires, fractal cloud effects, realistic water, rocks, etc. Where 'that' might be rendering hair, or modelling how skin creases at elbows. I modelled wood grain with a VAX in 1985 using a 24 bit monitor that cost more than some cars. Texture mapping is cheating.
Similar questions exist for modelling motion.
Sure, their output was often visual candy, but it was new and interesting regardless of jazz appeal. Its surface is powder. The 3D geometry yields 2D constraints on the texture that distinguish it from other striated textures. Turning the knobs generates different types of woodgrains.