At the time, I was bemused: why would anyone need to discover services? Surely they would be communicated to you as they were needed? But last night I realised the truth: Liberty thinks you need discovery because they think it is both inevitable and correct that all your data should live in silos, beyond your control, and ideally where you can’t see it. Of course, in this case, you can’t assist in the process of locating information about you. Nor can you detect, let alone correct, inconsistency and incorrectness.
This is clearly so much better than user-centric identity (where, in case it isn’t obvious, discovery would be unnecessary – you would just ask me where to look). I can see why Liberty is so keen.