Via Seeking Alpha:
The advantages to Nintendo are firstly that it makes their console cheaper to manufacture. This means that they can sell the base console at a profit whilst their competitors have to subsidise the retail price. It also gives Nintendo far more room to manoevre when it comes to using the price mechanism to take on that competition.
The second advantage is that games are a lot easier, quicker and cheaper to develop. In fact they are more comparable with PS2 games in this area. This, obviously, has a massive effect on what appears on the game shop shelf and when it appears. Quite simply, it should be far easier for a publisher to make a profit on Wii, which explains why so much development resource has been directed at it.