You are already putting copies of your fingerprints everywhere, by just touching stuff.

Fingerprints, like all biometrics are not a secret like a password. The point is to assess your physical presence. When used with a phone, your fingerprints are not securing your data, the phone, as a physical device does ("something you have"). The fingerprint is a second factor ("something you are"), a way to make sure the device is in your hands and not someone else's hand.

Security depends on the sensor device. That is, how good it is a making a difference between your actual, live finger and something else.

If you are worried about the security of your phone fingerprint sensor, use a password. Your fingerprint itself is already available to anyone who cares.