Every art has its why. Check out the wonderful work by @MadMaraca [1] as an example of what one can do with voxels. They're truly stunning. I think that the limitations of voxel art are also its expressive power.

Pixel art didn't replace at all painting, nor did it aspire to do that. But it founds its beautiful niche, and there's beauty in that.

[1] https://twitter.com/MadMaraca