I wasn't arguing that pixel art is easier to learn, but that people cannot tell as easy, if you are good at it.
A better example might be abstract expressionism. Regular people cannot tell actual garbage from art in that style. Of course we could argue, if it even is art or just pretend art, just as we could argue, if a photographer creates art. But let us assume that it is art and you can be good or bad at it. My point is, that casual observers will not be able to tell the difference, while they could for something more life-like.
So in a way, it is easier to produce results that look adequate at first glance.