What kind of witchcraft is this? O_o I didn’t even know that you could have dither brushes with pressure sensitivity in Photoshop, that’s great!
I only knew this method for dithering while drawing normally in Photoshop: http://danfessler.com/blog/hd-index-painting-in-photoshop
Thanks for the info @eishiya! 
I’ll definitely have a look at those brushes, is there any link you recommend?
Edit: I have found this one: aP's Dither Brushes by abductedPlatypus (it seems to work just fine ^_^)
And yeah, this would be an amazing feature for Aseprite!!