The fact anyone views this as anything other than paid on-disc DLC is truly baffling. Yes, you're getting a figure. What if you want to play that content, have those weapons, or play that character but don't want a figure? It's still $13 for what you want, which is in-game content, that would normally be available for much cheaper otherwise. Except, now you can't even control if you can get that content, because the figures might be sold out. Like the 3 pack for splatoon. Want all that content? Sorry, we may make more later for you to buy, maybe.
Amiibo started off as a neat "get a figure, get a costume" ideal, but it blew up into way more. There are 60 more difficult single palyer challenges, actual gear, etc locked out of Splatoon if you don't get not one amiibo, but the entire 3 pack - basically at launch, you have to spend $100 to get all the content for the game, except... you probably couldn't get the 3 pack, so really... you're screwed. They could easily put this on the eShop to buy, but nope.