TaZaR: Let me see if I understand. One of your arguments is as follows:
MSPaint is better than PSP because it doesn't blur things. I know PSP doesn't have to blur things, but then it's just as functional as MSPaint.

Yeah, I don't have much of a use for layers, but I know I'd have a lot of trouble doing anything at all if I was limited to three undos. I imagine it would be a complicated process of saving and reloading the image every time I thought about adding anything. And not having a palette or a simple "replace color" function would be pretty painful.