He simulated a screen crack over the Galaxy S10’s fingerprint sensing area with heavy scratches, and the S10’s fingerprint sensor stopped working.
That doesn’t mean a little scratch would disorient your Galaxy’s sensor, lighter scratches were reported to not affect the sensor. Nelson’s test scratches were deeper than what anybody would achieve over a lifetime of their Galaxy S10.
Most people should be protected from lighter scratches and even normal wear and tear, as Samsung is including a screen protector with the Galaxy S10. As for preventing cracks, suffice it to say that the best way to avoid them is to use a case.
Even though the fingerprint scanner stops working due to scratches, you could still make use of the facial recognition feature to unlock your phone, but the facial recognition isn’t the safest if you ask me.