I am reading a bit about the security of IoT devices and found quite a lot of articles describing how a PKI would be an improvement for the current infrastructure. I am, however, not convinced if setting up a PKI would improve security for most of the IoT use cases. I was wondering if I was seeing something incorrect. To give an example:
I understand how IoT devices used in Industrial Control Systems would benefit from a PKI, since they usually communicate without the interference of users and therefore cannot use traditional methods for authentication like passwords, biometrics and tokens.
For the more basic use cases like cameras, microwaves or refrigerators that are connected to the internet, I don't see the added value of a PKI. Am I overlooking something, or does PKI indeed not improve security for these devices?
Edit: some examples: