About the price one does not argue in my opinion, as long as the small figures are not required to play. There are still relatively few games that support this figure. I have worked with "Super Smash Bros. U" (SSBU) and "Mario Kart 8" (MK8) two of them. In addition, more and more games are supported so over time, so you get lots of little extras directly in a one-time purchase.
In SSBU obtained at linking the figure with the game a customizable NPC. This has a leveling system and a learning AI. Ie: Man playing with or against his character and with the time you learn this from a combinations and techniques. That is the theory. Practically it is definitely more at level up, but now that they would explicitly learn from itself, can not be determined. Nevertheless, it is certainly useful to be better to yourself when you play against a player who always represents a greater challenge. In addition, however, you can improve the characters individually with objects in the game (ie certain status values, ie increase attack, defense and agility) or provided with unlockable special techniques. But these do not represent exclusive content for the characters because you can improve such also the characters for human players.
It should be noted: You can associate a character with only one game. So far only the data cache to a game on the NFC chip of FIG. Requires a game store, you have to give up the data of the previous game. But you can still have recourse to additional bonuses in other games, otherwise they make no storage. For example, you can unlock in MK8 in conjunction with the amiibo figure a Link costume for his Mii driver.
As you can see, these are all features that have been built around the amiibo figures, only small optional gadgetry. This can be quite nice and allow extra fun, but you do not need. And it fits in my opinion. In addition, one obtains indeed the figures per se, which can be more than excellent. The figure obtained is very well made and does quite well on the shelf.
Who knows what Nintendo will begin with the amiibo technology or anything that I like the idea very far. The implementation in these games has come good. It will be added also certainly a few games at the Link figure I can imagine, for example, a again picking up in the coming parts of the Zelda series. Therefore, I would, as long as you not too much expected the friend amiibos well. Make already an added value. This, however, one should not overestimate!