Thus, I contend what would make it worthwhile is where the development is likely going, towards RL having a new optional-HD bust atop the CC3 base, matching the MetaHuman. So, when considered, you may as well apply 8.1 maps to a 8 and then you have basically what you would have had anyway, so there's not much point right now wishing for 8.1. This makes the 8.1 HD detail update pointless. BUT, one problem.CC will not import it in at HD, so, you basically get a down-res version.

And I say #4 is the biggest of them all, because that is where 8.1 could really stand out if brought into CC.

But so you bring that over to CC, and (1) you have a much much better animation paradigm given to you by RL, which makes the 8.1 facial posing stuff obsolete and redundant (2) you have DH Shader eyes which, if substituted for the Daz eyes, work and can look much better than the Daz 8.1 eyes (given they are fit properly), making the 8.1 eyes obsolete and redundant (3) you have the DH skin shader, which combined with Skin Gen will look better in iClone Real-time than any imported PBR shader Daz could, making the 8.1 PBR skin shader enhancement obsolete and redundant.

You know what the other thing is too- ask yourself, really, what does 8.1 give you, as a CC-user? Because within Daz, 8.1 gives you (1) better facial motion, (2) better eyes, (3) better skin, and (4) more detailed shapes.

Cc3 to daz