In Blender, dithering is enabled by default. First of all, it's not exactly true, that 8 bits per channel make it so banding is unnoticeable - but it's very har

In Blender, dithering is enabled by default. First of all, it's not exactly true, that 8 bits per channel make it so banding is unnoticeable - but it's very hard to notice; will depend on the area of colors (darker/brigher, redish/bluish...), but also if you dither your gradient in the image, and the image is further processed, the dither will help avoid banding after processing. Of course if you want to process an image, don't save it in just 8 bits per channel, but sometimes you don't know the image will be processed, or choosing the format is not up to you.