No it's not overkill, and no, fingerprints are not 2D. The fingerprint scanners on iPhones (and I believe other phones as well) are capacitive, meaning they rely on the physical ridges in your fingerprint.
http://qz.com/631697/a-regular-inkjet-printer-can-spoof-a-fi...
"The spoof worked on the Samsung and Huawei handsets, but not the Apple and Meizu ones"
cough graphite powder cough
>Fingerprints aren't 2D