I agree to some extent. I don't collect amiibo, but I currently own Villager (before he became "cool") and use him as my training buddy in Smash Bros. You'd be surprised how well it works. It's a limited system, but delivers on its promise. I have no intention of buying more amiibo for Smash Bros., though.
I'm also accepting of the fact that games use amiibo to unlock content (e.g. Mii racing suits in Mario Kart 8, or a special weapon in Hyrule Warriors). I don't mind if amiibo is used to add completely unnecessary elements to a game (e.g. Toad "hide and seek" in Captain Toad).
However, and this is where I draw a line, I find it unacceptable if not having certain amiibo locks me out from a portion of the game completely and Nintendo has demonstrated they're going down that route. Mario Party 10 will have a special mode ("amiibo Party") that's only available if you have amiibo (presumably from the Super Mario wave of amiibo). The trailer shown during the Nintendo Direct clearly detailed a lot of content (various boards, items, etc.) locked to this mode. I really don't like that at all. It's one reason why I'm not getting Mario Party 10 (with the other being lack of online play).
It's disgusting that Nintendo is using amiibo this way. I'd understand if we're talking about small content like what amiibo has been used for previously, but to lock a player out of a lot of content and requiring amiibo to access it, is in my opinion not good. I was open to the idea of buying more amiibo if more games supported them in meaningful ways as in Smash Bros., but this decision from Nintendo has ultimately made me decide that Villager will stay as my only amiibo for now.
And let me take a minute to count the times I said "amiibo" just now. Wow.