I agree with you 100%. But I think it would be more about a branding issue. People know what amiibo is. Nintendo would not have to do too much advertising to get it to sell. And it's a good way to get the more niche characters into the game and advertise them so when their separate games come out, people already know the character. The same thing happens in Smash bros all the time. Also you could also make up a totally new character amiibo for the amiibo game as a test. To see if there is enough interest in the character for someone to make a totally new game based around that character.
I get what you are trying to say. And this would be Nintendo's choice to make Amiibo more than just the physical figures. In Smash Bros it feels like that. Sure you still have to tap in the NFC chip but you are fighting the amiibo in game. And that's the issue we have. If you make it about the physical figures only, then supply constraints will anger people when they can't find their favorite character to tap into the game. But if you have the digital amiibo as well then there's no supply constraint issues but then some people might get the feeling that the physical toys feel a little irrelevant as you say. Just a few points to consider.
Wait, now that I think about, the branding issue makes sense, but it still sounds weird though.
The thing is, I was under impression that the Amiibo concept was an extension/offshoot of Smash Bros., so when the idea that "here's game centered on Amiibos" isn't that just "Smash Bros."?
I know Amiibos have expanded beyond Smash Bros. but that's what it started out as.
Another thing I worry about, putting aside the physical Amiibos, you mentioned before downloading digital Amiibos that cost money, isn't that just a regular microtransaction? What it seems like you're suggesting is making a game where you pay 5 to 10 $ to buy playable characters, and they have different abilites stats. etc., do you really that sounds appealing? Didn't certain microtransaction have a bad rap recently? All I'm saying is I worry how they might be handled, I know Nintendo is not an EA, but still.