There's a great deal to be said for setting an aesthetic expectation.

Take Minecraft, for example. The most successful game of all time along many axies, and it looks .. a certain way. It's definitely not realistic. It's not even pretty in a lot of cases. But it's consistent, and people have pushed it to the limit and created some truly beautiful artwork.

I guess what I'm trying to say is that I think visual fidelity can be a selling feature, but art-style and consistency is much more important.