Here's an observation: While watching the Super Mario Odyssey portion of today's Nintendo 3DS and Switch livestream, there's an interesting trend with Nintendo and amiibo lately. Basically, in a soft way, amiibo are becoming Nintendo's take on pay-to-win type systems.
In Super Mario Odyssey, players can hunt for Power Moons which you'll need to collect to progress in the game. Some are in obvious places, or rewarded for defeating enemies while others are apparently really well hidden. There are ways in-game to find them like asking Toad for hints, but players can opt to purchase an amiibo that will unlock more hint generating characters.
While I don't think Super Mario Odyssey will be impossible to beat without amiibo support, the concept of paying for additional content to help players complete the game is essentially what the pay-to-win situation is all about in other games. The only difference is that Nintendo's system gives players a collectible figure as well.
This is similar to a feature in Metroid: Samus Returns where the Metroid amiibo will unlock a hint service that will locate the nearest Metroid. Again, this isn't necessary to complete the game, but given that the point of Samus Returns is to defeat all the Metroids in the game, it is something that helps players finish the game.
Nintendo already drew some controversy with the amiibo support in Samus Returns after locking Fusion Mode behind an amiibo, which is separate from a Hard Mode that will unlock for all players upon completion. Still, it is a feature that players won't have access to unless they pay extra which makes it closer to product-based DLC than a pay-to-win system.
The hint generation unlocked by purchasing separate amiibo is crossing into weird territory however, and is a very Nintendo-like approach to a game system that's steadily becoming more common in modern games. While Nintendo's approach isn't exactly pay-to-win, it is interesting that amiibo are now acting as Nintendo's physical DLC unlocks.