What Nintendo Switch's Launch Success Actually Means

Nintendo has offered preliminary word of the Nintendo Switch's launch success, as well as The Legend of Zelda: Breath of the Wild, in multiple territories throughout the world. But what do those statements actually tell us about the launch, and are they any indicator of the Switch's longevity?
Statements and data regarding the Americas, Europe, Japan, and now Australia have been revealed, including what Nintendo touts as the best-ever debuts for a system in Europe as well as in North and South A