Earlier quoted context omitted.
Only if you want a dithered look, which oftentimes you don't.
I guess it depends on the size of your pixels. But as long as your pixels are small enough, I think this is the only way to have a gradient go straight from one colour to an opposite colour without going through either grey or a multitude of other colours.
Pixels are much larger than imperceptible, even on "retina" devices: https://jacksonkearl.github.io/canvas-thing/