[shadowfaxRodeo]

Hi there author of the article here, I did a lot of testing when I wrote the article, and even made a tool for dithering.

https://doodad.dev/dither-me-this/

It completely depends on what kind of dithering you do — ordered dithering with a small color palette will give you a much smaller file size than a full color jpeg.

WebP and AVIF also support lossless compression and can be used for even smaller file sizes using dithering.

[LinAGKar]

Depends on the quality level. In my test, recompressing the original as JPEG quality 12 (with ImageMagick) gives approximately the same size as your 12 color 4x1 dithering, but at better quality (though it's miscolored in places). Webp quality 11 also gives approximately the same size, but looks way better.

I suppose you can argue whether the JPEG artifacts look better or worse than the dithering, but WebP definitely looks better.

[thrdbndndn]

I didn't seem to find a 8-bit preset (what OP mentioned) to test how it would look like compared to true color images.