Presumably, Nintendo provided rival gaming companies with their prototype white disks for use during the game development process. The reason that's believed to be true is because of this disk. It's Dr. Chaos: Jigoku no Tobira, released by Pony Canyon, not Nintendo like the copyright on the label suggests.

Dr. Chaos, released by Pony Canyon.

Protos sell for about $80 in Japan. You can imagine that the better the game, the more for which it'll sell.