You want triangles in general, they behave way better, think for example computing intersections.
Also, debugging colors on a 3D surface is not an easy task (debugging in general in 3D is not easy). So if the rendering is nice and seems correct, you tend to think it is.
And if it was not, and you didn't encounter something that bothers you, it doesn't matter that much, after all, what is important is the final rendering style, not that everything is perfectly accurate.
Also, debugging colors on a 3D surface is not an easy task (debugging in general in 3D is not easy). So if the rendering is nice and seems correct, you tend to think it is.
And if it was not, and you didn't encounter something that bothers you, it doesn't matter that much, after all, what is important is the final rendering style, not that everything is perfectly accurate.