It does not have non-destructive editing layers, color correction layers, indexed palette, posterization, as in Gimp or Krita,
it does not have the ability to draw with higher resolution brushes for subsequent resolution reduction, etc.;
it does not have shader graphs, as in Blender, Pixel Composer, PixelOver;
it is difficult to draw in an indexed palette, unlike PixiEditor,
you can't take 3D renderers and transform them into pixel art, like in PixelOver or Blender,
and there's no bone animation for 2D, like in Spine.
Aseprite is a good editor if you like to paint pixel by pixel every frame without using the advancements and workflows that other style designers and artists use, but calling it the best would be an exaggeration.
It depends on what you are doing. I really like it for creating animated characters. Resprite has some nice feature for creating tilesets. Standard raster editing software might be better for big static scenes.
it does not have the ability to draw with higher resolution brushes for subsequent resolution reduction, etc.;
it does not have shader graphs, as in Blender, Pixel Composer, PixelOver;
it is difficult to draw in an indexed palette, unlike PixiEditor,
you can't take 3D renderers and transform them into pixel art, like in PixelOver or Blender,
and there's no bone animation for 2D, like in Spine.
Aseprite is a good editor if you like to paint pixel by pixel every frame without using the advancements and workflows that other style designers and artists use, but calling it the best would be an exaggeration.