I think it is an excellent choice for Nintendo, but some people get the disc confused as just another form of the expensive cartridge choice. It isn\'t. Cartridges are extremely pricey to manufactor, where as the mini-disc isn\'t. And just because it is a proprietary format, doesn\'t mean it will be expensive. Remember, the GD-ROM was for Sega, and it was no more expensive (maybe less expensive) then the current PS2 games that are on DVD.
The GC can compress textures at a 10:1 ratio, which saves a huge amount of space for the disc. Then, take in account if for some reason the game needs to be larger they can always throw in another disc just like in the regular CD days. There is little reason to think the small disc will deliver a smaller game then the PS2. As it currently stands, none of the developers are taking advantage of the massive space on DVDs and when they do, it will probably be mostly fancy cinemas.
Also, SonyFan does bring up a good point. Due to the format being proprietary, Nintendo could charge as much as they want for the games. I don\'t think they will, but they could. One of the biggest flaws for the N64 was the cartridge format and the price of games. Legend of Zelda: Majora\'s Mask is $70 dollars! So is Conkers Bad Fur Day. That is alot to pay for a game. We will have to wait and see if Nintendo is going to charge us out of the ass for GC games, but I doubt they will. If they charged near $70 dollars for a game this time around, it would be suicide.
But, piracy will continue. Matsuhita will be producing their own version of the GC that will play DVDs, so in theory someone could copy the contents of the Mini-disc onto a DVD-R and then use it on that unit. Of course, for this to happen DVD recorders would have to come down on price and become more mainstream. When this happens, Sony will also find itself being pirated like with the original PSone. And there is no \'fool-proof\' way for Nintendo to gurantee no one pirates the games. Remember folks, there is always someone out there that is looking for a way to get free games and there is always a way. Just takes one guy (or gal) with alot of free time to discover it.