Digital certificates do not ensure security by themselves — their efficacy depends on how well they’re managed. In-house PKI management is not a viable option for IoT devices owing to their sheer number. A factory could easily be using thousands of IoT devices, and managing their certificates in-house levies an unnecessary strain on resources. Moreover, even one expired or compromised certificate left neglected can wreak havoc on the whole network, leading to outages and potentially hidden rampant attacks.