https://www.theverge.com/2019/3/1/18246289/samsung-galaxy-s10-fingerprint-reader-scratch-crack-test

Yesterday Samsung confirmed that the Galaxy S10 and S10 Plus will ship with a preinstalled screen protector. But if you’re not a screen protector type of person, you can rest easy knowing that the ultrasonic fingerprint sensor on both phones can withstand plenty of scratching and still function properly. Zack Nelson put the S10 through his signature durability test at JerryRigEverything, and as usual for Samsung, the company’s latest flagship proved well-constructed.

However, we haven’t seen too many other smartphones with the ultrasonic in-display fingerprint reader that Samsung built into the S10 and S10 Plus. It works when your fingers are wet — a common foil for traditional capacitive scanners — and it’s supposed to be faster than the in-display optical readers used by OnePlus and other companies. But there are always questions about new technology and durability. Can scratches from common wear and tear interfere with the sensor? The answer seems to be no. Zack caused plenty of scratches on the area overtop the sensor, and it seemed to work fine.