Touch ID has been very successful on the iPhone 5s, increasing both security and convenience. It's rumored that Touch ID will now be on all new iOS devices, including the forthcoming iPads.
Today's announcement was another highly requested feature: the availability of Touch ID on third-party apps. Until now, Touch ID was restricted to turning on your device and accessing your account in the iTunes Store. But now, for example, if you use a banking app, your bank will have the option of implementing Touch ID, such that you can access your account without logging in but simply using the security of Touch ID.