I have about a dozen services defined under my name, some of which are private, which I can prioritise, or even change to a different profile depending on time/location.
Mobile operators are starting to adopt it, despite the fact it undermines their phone number lock-in, because it makes it much easier for them to roll out new data-driven services, e.g. China Mobile (600m subscribers) will use it for mobile payments.
It could be even more interesting if device manufacturers ever manage to persuade mobile operators to use virtual SIMs - imagine being able to subscribe to new networks on-the-fly!