Is Fingerprint authentication is as good as modifying Shared Preferences?

Question

I am adding fingerprint authentication in my app at launch I read a boolean variable from preferences to decide if fingerprint authentication is enabled or not. I am wondering how easy it is to modify shared preferences of another app. Seems like its really easy thing to do Android: Modify SharedPreferences of another app.

Does this mean that fingerprint authentication used based on shared preference is useless?

Every sample that I found relied on such preferences. E.g. https://github.com/googlesamples/android-FingerprintDialog

Answer 1

I once modified my App's Shared Preferences XML file manually without any issue, so I guess it is not safe to store that config value there.