I got hooked on Aseprite's gradient tool as well. It'd be so much work to hand-dither everything (which by the way, in the attached picture this looks incredible! Really pushing the 4 color palette to its limits). I wonder if there are plugins for different gradient patterns, maybe I could try it as a side project. I don't have the drawing skills myself so I could really use something like that. (Edit: here's one on itch, and here's another plugin that specifically has blue noise)
Edit 2 (sorry): A good visual comparing ordered dithering vs blue noise



