Gameplay comes first, while eye candies come as a bonus.

Good graphics can fool/blind some players to believe that the pretty looking game has delivered well in it's gameplay area, which IMHO happens toooo often. Esp when fanboys start to fight over how superior their "pretty" game is. zzzzz.

Nice graphics enhances the experience and making player stop to take a look around to see if they had miss a thing or two. Like easter eggs, or just plain miscs.