Thereby there is no reference cipher block to aid analysis. used to encrypt unique data like user data that will be different from device to device.
Unique keys are best employed when they can not be compromised in this way, i.e. Using tens of millions of unique keys (one per PS4) to encrypt identical data provides a metric shit tonne of cipher blocks to analyse and improve the decryption algorithm.
You've not really said why you think this but it's a view I've encountered a lot over the years and is counterintuitive or rather, endemic of dated thinking that encrypting everything is better.
