Fraudsters (from script kiddies to nation-state actors) still pass verification despite multiple security layers. Legitimate users are unexpectedly rejected or unable to complete onboarding. System decisions remain difficult to interpret even for experienced operators.
“Digital identity is the unique representation of a subject engaged in an online transaction.”
For a practical understanding of how to build and exploit trusted biometric identity verification systems, read 3DiVi's Threat Model for Remote Biometric Identification White Paper.