I still don't get the point. Why use them? I don't want to play a machine, I want to play a person. If I'm going to play against a machine, it should be clearly known to me before the game starts and I willingly consent to it. Sneaking one in is cheating or something else. It's definitely not sporting or fair.
Dark Chess is probably the least machine played game, plus it's hard to get outside help from other people because of the darkness.
Seeing how a person can take atleast a day for each move, I really don't see much need for a machine to make the moves. Just being lazy, eh? I ain't buying it for Reversi, Chessmaster1000. You don't need the machine to make your moves for you. When it's your turn, make a move. If it's a bad one, then too bad. If it's a good one, you earned it. Rationalizing away the reasons for your using the machine doesn't negate the fact that you're using a machine to play your games.

I imagine in ten or less years from now, computers will probably play these games so good that they'll stop being much use in having tournaments for them. Then the rest of us regular folks can just play them for fun like they're supposed to be.