The tip of my right index finger is frequently subject to wear, dry & peeling skin and general attrition fro guitar playing (among other things). This does not make for a reliable recognition when using a fingerprint sensor.
I know the sensor works OK because the other fingers I have set up work pretty much first time, every time, although having a slightly deeper case on the phone has reduced reliability because it reduces the contact area of the fingertip.
Guess it's slightly reassuring.
In other thoughts, Apple may be a better supplier of hardware than many others. It has nothing to do with the actual hardware and everything to do with the fact that they're a hardware manufacturer who doesn't have a business model based on selling you, the user, to advertisers and others. It's not that I think they are now a good, friendly, ethical company - absolutely the opposite - but their business model is becoming focussed towards selling secure devices to wealthy people, and sales would suffer if they thought their devices were not secure.
Having said that, the reality distortion field around Apple hardware has been such that at times, leaky security would have been presented and accepted as a better thing than selling secure hardware. Never believe the promises of someone looking to make money by selling you stuff you can't understand.