>>11862938 (OP)It had absolutely nothing to do with piracy, and was instead an effort to do the minimum amount of work to make a DVD-like format that's technically legally not actually a DVD so that Nintendo could avoid paying patent royalties to Sony
They did the same thing with the Wii discs where they actually figured out a way to make them full-size, and the WiiU which actually had slightly more effort put into making their I Can't Believe It's Not Bluray discs.
The most obvious flaw in the anti-piracy argument is that the disc drives in the Gamecube and Wii can still read standard DVDs just fine and all the copy-protection is at the software level. It wouldn't even have taken that much effort to do mechanical adjustments to make reading regular DVDs entirely impossible.