There's a legal difference in some places between having your phone secured by a fingerprint and a password. If your phone is secured by a password, then in some places you cannot be obliged to provide the password, but a fingerprint you can.
There was a bunch of reporting in the past few days that a Federal District Court in Pennsylvania found that Fifth Amendment rights apply to smartphone passcodes.
Random link: http://www.digitaltrends.com/mobile/why-the-government-cant-...
That same protection doesn't seem to apply to fingerprints. Random link: http://time.com/3558936/fingerprint-password-fifth-amendment...
Again, I'm not a lawyer, but that seems to be how the law falls out on that issue.
Whether that's an issue for you, personally - no idea. It might be a factor for some.
One of the neat things about encryption, historically, is that the government couldn't force decryption even if it were willing to break the law in doing so. That's why there were export controls and demands for backdoors in the '90s, and that's why there are demands for backdoors today. Fingerprint locks may mathematically involve encryption, but they don't have this property.