The microcontroller, smart card interface, eInk screen, bluetooth capability (including antenna), NFC (including antenna), and touch screen all seem reasonable and there isn't anything earth shattering tech wise (but probably a customized asic using off the shelf bits). Connecting this all together on some fiberglass or plastic substrate is hard, and expensive to tool for (I'd expect), but definitely possible.
The interesting bit is how they're fitting the battery and getting anything remotely like reasonable life. Even down in the single digit micro-Amp consumption range (typical for low power microcontrollers plus some resistive touch), a battery small enough to fit inside a credit card will likely only have a few mAh, at best. This will lead to needing to recharge quite often if the bluetooth turns on or eInk screen updates more than once in a blue-moon.
The interesting bit is how they're fitting the battery and getting anything remotely like reasonable life. Even down in the single digit micro-Amp consumption range (typical for low power microcontrollers plus some resistive touch), a battery small enough to fit inside a credit card will likely only have a few mAh, at best. This will lead to needing to recharge quite often if the bluetooth turns on or eInk screen updates more than once in a blue-moon.