On one hand, I appreciate this a lot as it's been baffling to me that this aspect of Zot wasn't adopted during development of ActivityPub. On the other, I kind of feel like some of this forgets or overlooks the benefits of running fully separate identities.
I recognize that the article points to this easing that process in a way, but it's pointing more to facets of a single identity, which benefits from some degree of interchangeability depending on those facets. This is clearest in the notion of retaining one's connections with minimal disruption should one facet's instance/host go offline for some reason, but also in it being relevant to maintain the same content between facets.
This has sort of also been the issue some see with the idea of federation and the fediverse itself. Some people enjoy the different styles of posting and interaction across different non-federated/linked sites/platforms, yet in some ways federation tends to blur or break those distinctions and try, sometimes clumsily, to blend it all together. For those all in on the idea, that's a major bonus, but for those not sold on it, it's a major pitfall.
In some respects I think this may kind of help those wanting to maintain different identity facets around here, but may also create a potential tripping point for those trying to more easily maintain distinct identities depending on implementation.