what separates this from other digital art?
I kind of see your point. If this is a pure pixel art thread, then there may be a point in keeping it pixel-only. But I don't see any reason to be that strict, unless the thread gets overrun with filtered stuff.
I could do what he's done within an hour, splash a layer over my work and now it becomes cool?
This, however, is the poor attitude that was apparent in your first post as well. If the end result looks cooler, why not do it? Criticising the method for being "too simple"
misses the whole point of art and being creative. If you wanted to criticize the actual content you could have said something along the lines of: "it looks generic due to the filters"
(I still wouldn't agree with you, but it would be valid criticism)
Personally I like that people are experimenting with filters and pixels, taking the best things from both worlds.