- use in emulators to upscale retro games to fill high definition displays;
Looks ugly.
- print in bigger sizes: for cards or t-shirts as the guy above said;
Again, just use clean scale.
- or just for apreciation.
Do you suddenly appreciate the pixelart more when you are looking at upscaled, filtered versions which destroy the clusters layed down with intent by the artist? I am not seeing it.
IMO any form of filtering that distorts the shape of clusters a pixel image originally had is not a good way to treat pixel art.
That said, I can appreciate the programming behind this. I just don't think it has any useful application, personally. At least I can't think of any.