It is disc locked content actually.  With SSB, the AI and customization data is stored on the Amiibo, but all the content for that comes on the game disc. 

The Amiibo working on multiple games is further proof of it.  You buy an Amiibo when SSB comes out.  You use that same Amiibo on a game that comes out a year, maybe two years later.  Obviously the data for the game can't already be on the Amiibo.  Whatever the game uses the Amiibo for, it downloads that data to the Amiibo.  That means that the content is already on the disc and only with the Amiibo are you able to use that content.  Hence, disc locked content.  

Not even similar.

That isn't the same thing at all.  The thing you aren't getting here is the fact that there is information on the Amiibo on the disc, yes.  But that's for compatibility.  The actual part of the Amiibo you use is stored in the figure.  The disc may feed the Amiibo figure the information like the AI patterns and stuff, but the thing about it is that you're comparing it to paying for content locked into the disc in order to progress in the game or some kind of unlockable character.  It isn't.  You aren't unlocking a new character with the Amiibo, they are existing characters and they are used in ways DIFFERENT than DLC... because it isn't DLC nor is it advertised as such.  It's a tangible AI partner for Smash, and most likely some other kind of side thing.  The price of the figures aren't even going to be unreasonable given that you're pretty much paying for the figure, not the content.

Whether it will be successful or not is a different story.  Also whether or not the use of the Amiibos will be any good depends on the person.  You're acting like this is some kind of underhanded thing to do, but it really isn't.

I hope these figurines are individually identifiable in some way. I can see kids fighting about who's Mario is who's - especially when one is trained to a higher standard than the other...

It's quite a cynical move, but the presentation as cute figurines is what's throwing a lot of people off.

So.....by the terms of your own argument, it's not disc locked content then?

It's "borrowing" content from the game and storing it: the content is accessible without the figurine. It's a glorified memory card. I don't think you're using the term the way everyone else does.

Because no has been praising them, lier

Nintendo can do no wrong in certain fans eyes.

Except that's not relevant here because there really aren't that many people actually "praising" Amiibo.  Most of the reactions have been neutral at best.  And the comparison being made in the OP is just wrong.

My point still stands overall.