I like how Nintendo is trying to establish some sort of identity with amiibo, but the amount of games they're used for is kind of low; and in some cases, frankly mis-alligned in terms of player genres. like before Mario Kart; what game would Pac-Man be used for other than getting 1UPs in Captain Toad or Smash? his "main" usage for Namco is Ace Combat....
In Sonic's case it might be a bit worse since he rarely has games that often, i wouldn't be surprised if they bring him up for the next Mario and Sonic game and that would be it. Smash is essentially the vehicle for gaining sales for amiibo, but other than that, they just kind of sit there. though as far as Nintendo merch goes, they're kind of quirky, and is the only way that some franchises would even get merchandise in the west like Earthbound. they're no Figma or Nendoroid, but for £10-14, they're pretty OK. just that the realistic human characters tends to have that painted-on-face syndrone whilst other characters are much more closer to their game's representation.
There's even some flaws, but that's due to the molding process and in no way causes fragileness. so Diddy, Mario, Pikachu and Bowser is spot-on, but DK's hyper realistic fur translates even worse in real life, and the mold "flaws" i was talking about is really noticable around DK, Diddy and Bowser's mouthes, the most latter even looks like a Kubrick stare. Yoshi too has little mold joints, but he's pretty cartoony....just wait for PAC-MAN, those suction cup-like joints will look 100% for him.