Animal Crossing: City Folk, the first game to support the WiiSpeak peripheral, and the game most closely associated with it in the public consciousness and Nintendo marketing, is also the perfect argument for the device. Having been designed as explicitly multiplayer, Animal Crossing is an even more communal experience. It is communal in the home in the same way that Wii Fit is, designed for people to watch and take turns, and it is also playable simultaneously online. It is a game about communication.
Since so much of the gameplay is tied up in what other people are talking about, were you to wear a headset, that dimension of gameplay would be lost to the family gathered around the TV. Not only that, you would be lost to the family gathered around the TV. It makes no sense for you to have private conversations in a family Wii game.
In fact, since Animal Crossing is about communication more than anything (now that the NES games are gone), opening up the conversation opens up the gameplay. Anyone in the room who is talking to your online buddies is, in a significant way, playing Animal Crossing. It's the equivalent of the Co-Star Mode in Super Mario Galaxy.
If nothing else, WiiSpeak should make the experience of being in the same room as someone playing games a more coherent experience, if not more pleasant. People nearby will be able to hear both sides of your in-Conduit conversations, for example, and, if they aren't already familiar with FPS games, may come to understand what's going on a bit more easily than they would if you were just yelling strategy and/or racist trash talk at your TV. It could be a learning experience.
It may hurt to hear this, but the Wii is just different from the other consoles. Even online, it's a party console. Very little about it is designed strictly for the individual. The WiiSpeak will work fine when you're alone, but it will excel when you're playing around others.
