Android 5.1 vs Android 6: Fingerprint Support
Android 6.0 Marshmallow finally has native fingerprint support for devices with a fingerprint scanner. Which, these days, is almost every phone. This means the features for signing into apps, Google Store purchases, mobile payments and more are all natively supported by Android, and more developers can get on board. Rather than trying to partner with just Samsung, or other OEMs. We can pay for apps using our finger, rather than typing in a long password.
With Android M users can unlock the device, make app purchases, sign into websites or accounts, use Android Pay and more all with their fingerprint. So long as the device has a fingerprint scanner. There's no screenshot for this on Android 5.1, and we don't have the new Nexus devices yet, but it's called Nexus imprint, and Samsung integrated much of this into the Galaxy S6, Note 5, Galaxy S7 and more.
This should bring improved security, convenience, and better Android Pay usage to Android devices.