This thread is very odd because people approach this issue very differently apparently.
Is your fingerprint considered data or a password? The intent of OEM's (apple, android, laptops whatever) is your fingerprint is a password although people here are treating it as data.
Think of it this way, are you scared of the evil hackers getting your password or the data protected by your password? By itself your password is meaningless i.e. I tell you the password on my phone is "!@#$%^" and that does you absolutely no good.
I completely understand your fingerprint has larger implications than just unlocking a phone and is unique identification to you, but at the time writing this, stealing fingerprints as a form of identity theft is the stuff of movies. Unless you work in a nuclear weapons facility odds are someone having your fingerprint is about as valuable to them as your "!@#$%^" password.
That all being said, IMO the usefulness and validity of a fingerprint reader on a phone should be measured by security and convenience. The fundamental questions are:
If you use a fingerprint are people more likely to steal your data than if you used a password?
Is the fingerprint reader more convenient than a password or pin?
I just find it funny people are so worried about their fingerprint getting stolen yet they'll access their banks from their phone and they feel secure doing that. There's even a thread of people up in arms because they had to set a lock screen (even just a pattern unlock) to use android pay and they think that's crazy.