And what would expect the amiibo to do? I'd much rather it be something pointless like this than locking major content like it was in Twilight Princess. Amiibo are a bad thing in general, but you can't really expect Nintendo to stop making them, and they will always put some kind of in-game use for them since that's (supposedly) the whole appeal of the concept.
I feel this is the exact opposite of something pointless, though. Whether you feel it's a needless cheat code or not, it's a feature. It's not actually that different from Twilight Princesses feature being locked behind amiibo, other then that was a bigger feature being locked behind amiibo. The most pointless amiibo inclusions are when you just get something like an easily-accessible collectible in game through scanning an amiibo, like the ones where you can only scan an amiibo once or twice a day to stop farming of things you can already easily farm in game, which is usually the most pro-consumer ones because you don't need to buy an amiibo to access that content. It's not a feature that you otherwise wouldn't have. It's just something regularly in the game.