Yes. The claim that you don't need more than 3 decimal places is laughable. Your artificial design doesn't need decimal points. At all. You probably can do even better by ignoring the last 4 bits completely.

That said, the article is very interesting, and that claim applies on different contexts. It's just aimed at the wrong one.

For gradients it definitely isn't unless you have the ability to do FRC dithering where the dither pattern changes every frame. The banding is very noticeable on a large enough screen.