Earlier quoted context omitted.
When Apple introduced a fingerprint unlock in the home button, it wanted to keep the fingerprint scans secure. The security chip that stores the fingerprint scans needs to verify that the home button's fingerprint scanner is trustworthy, to prevent man in the middle attacks. However, when an unauthorized or unofficial button is used as a replacement for repair, the phone will permanently brick itself. No warning is g…
As a user, that’s what I’d want it to do. If someone is trying to bypass the fingerprint sensor by replacing it because they know that’s where the authorization is stored, that’s exactly what I’d want the phone to do.
If a compromised scanner fails to authenticate, then the security chip can just ignore the scanner. Not much it can do if its only avenue of communication is cut off. A warning message telling users to not touch their compromised fingerprint scanner would have been sufficient.