And you could/can unlock TouchID with playdoh casts, even high res fingerprints printed on paper... so?

Printing someone's photo off Facebook is trivial.

Lifting a working fingerprint and transferring it to a play-doh mold or a hi-res printer is a whole another beast.

I thought it needed to be a high resolution photo?

For Samsung, nope. You can just open someone's profile picture on Facebook on your phone and show it to their phone and It'll unlock (or not, just like with their actual face).

Samsung didn't do face unlock first either, it was part of Android 4.0. Of course, using a single camera without movement you'll only get 2d data, so it shouldn't stand a chance against Apple's 3d sensor.