Earlier quoted context omitted.
Why?
Diffusion works significantly better for images than sequential pixel generation, there is a good chance it would work better for language as well. Sequential generation used to be state of the art in 2016 and it's basically how current LLMs work: https://arxiv.org/abs/1601.06759
A fairly new but promising approach for autoregression that seems to scale as well as diffusion is predicting the next image scale/resolution rather than the next image patch.