It seems to be amiibo day, with a Wii U system update adding a settings menu for the figures and a range of 11 more toys confirmed for 2015; those are positives, though details on how to use the figures on the official website in Japan indicate some limitations to the figures.
Though it's been communicated previously, this page once again clarifies that while Super Smash Bros. for Wii U reads and writes the data on the figures, early titles with support detailed — namely Mario Kart 8 and Hyrule Warriors — will only read data from the figures. To clarify, Smash Bros. saves the progress of your amiibo — which we've detailed here — while MK8 and Koei's action title simply recognise the amiibo (in terms of whether it's Mario, Link etc) and activate pre-programmed extras, in the form of Mii race suits and items.
What's emerged from the official information is that the figures will only store data for one read / write game at a time; if you want to switch an amiibo from one such game to another, you'll need to use the Wii U's amiibo settings to clear its data first. That's not a problem right now, as Super Smash Bros. for Wii U is the only game writing data to the toys, but will surely become an issue down the line. There are potential workarounds, such as a game storing backup amiibo data for you while you wipe the toy's chip to use it elsewhere, though Nintendo tellingly isn't mentioning that as a possibility at present.
Ultimately, this first batch of amiibo is branded for Super Smash Bros. and will support other games with more basic functionality. By opening up the toys to work across a number of games, however, there's certainly a danger of confusion the moment a second read / write game arrives, as you likely won't be able to use your first batch of toys fully without losing Smash Bros. progress.
Let us know what you think of this — does this bother you, or do you feel that it's a logical approach from Nintendo? Let us know.