[cantankerous]

The image aesthetic is emulating the appearance of a dot-matrix printer. It's just a low-tech motif to go with the publication.

[mistercow]

That would be all well and good, but the page specifically claims that using dithered images lowers energy use.

[moron4hire]

They may have ran metrics on decoding processing time neé energy usage

[mistercow]

I doubt it. The only study I could find on energy usage in image decoding was this

https://ieeexplore.ieee.org/document/7168333

which found JPEG decoding to be much less energy intensive than PNG decoding, mostly because it's faster. Note that that's not just a function of file size, as lower quality JPEGs actually took more energy to decode.

Which all makes a lot of sense when you consider how much work has gone into optimizing frequency domain based compression and decompression.