Ammiibo hacking is buying the basic version of a software program, and then bypassing the security code that protects the pro features.
It's the same as piracy, which you may considered a vice or a virtue.
I'm not sure the majority of people would pay Nintendo 50 bucks for this certain Amiibo, but I'd bet it would be quite a few more than those who will pay a reseller.
Anyway my point wasn't to support or deny Amiibo hacking, just to highlight the contrast between basic/pro software versioning and Amiibos.
And to top it off; you can't buy a key for the pro version!
My argument relies that beside the difference in functionality, the real separation between a basic and a pro version of a software is a license.
If we where to draw a parallel between basic/pro software and BOTW, then we have Nintendo producing a device that more or less gives anyone who touches it unboxed a license to use the pro version of the software, and is trasferable/resellable.
Now, this "license" might not grant right to copy and redistribute, but since it is not exclusive per se it should be equivalent to let a friend use it or "clone it" and send it to a friend, therefore reducing the piracy question to "is it piracy to use someone else's amiibo (with is consent)?". I think the answer to the latter is no.
It seems very similar to cracks that spoofs USB dongles to unlock pro versions of software. I guess you could argue the unlocked accessories are purely cosmetic but I don't think you can really get around the fact that the accessories are pirated.
I understand gamer's frustration with paywalls and pay-to-win, but let's be real here. These are collectible figurines and fun cosmetics inside a game. No one is forcing anyone to buy these and Nintendo has every right to do limited runs on some Amiibos. That's half the fun if you're into collecting these things.
If it's understood that I will never have a skin/level/weapon because I didn't purchase something additional besides the game, I just weigh whether I want to make that purchase. Just because a feature can be unlocked via a code doesn't necessarily mean I have a right to it outside of purchasing that code.
This is hardly Destiny where you paid the same price for the game, but some of the userbase got access to more content based on their console and that content never got released on other consoles (not that I'm bitter or anything). Here, you pay if you want it.
They have every right to do limited runs, I have every right to do everything in my power to bypass that. I own the console, it's processor and memory after all. This is the nature of writing software that runs on a computer that someone else owns - ultimately, they have every right and power to decide how it runs.
Legally, meh, probably not so much.