Almost all virtual worlds include games. Typically, playing the games is the avatar's 'job' and by doing so players can upgrade their visual representation with fancier looking avatars and fancier looking virtual living spaces. In essence, the players are buying status.
If this mechanic is the centerpiece of your VW's economy, for the love of pete, please make sure the games are fun.
Is it better to have games that use the player's personal avatar and are fully integrated into the world itself if they aren't fun? No.
Best: Fun games, fully integrated in the world.
Okay: Fun games that aren't directly connected to the virtual world.
Disaster: Un-Fun games, integrated or not.