Ability to play smaller discs was normal in most CD-ROM and DVD players for many years before the Wii. A few people (probably half of whom have HN accounts) used to give out mini-CD business cards...sometimes even with truncated edges so the disc was not entirely round: https://www.duplication.com/cd-business-card-duplication.htm
Yeah but most of the optical drives that support this have trays or are top loading. It’s a little more counterintuitive to have a postbox-style drive (I don’t know what they’re actually called) that supports different sized discs.
GC emulation wasn't emulation; it was done with a separate chip. It was more like native support. Eventually Nintendo removed that chip and backward-compatibility support from the console.
(so, even if you could put a GC disk in, it didn't have capability to natively play the game)
It sounds like you're confusing the Wii's backwards compatibility with the PS3's. The Wii didn't have a separate "GameCube chip", its core was effectively an overclocked GC.
