Hi Peter + all,
They are working spaces… a few of the benefits are a 10 bit, bespoke TRC, and being able to utilize a gamut that is generous but not overly large and thus more efficient. Also, the associated chroma variants are such an elegant way to influence colorfulness in PS. I am a big fan of them, and his work.
I render into DCam 3, J Holmes from Capture One. If you want to use Adobe, it is easier to accomplish via ACR in PS or Bridge. One of my long standing feature wishes for LR is allowing any profile to be selected when round tripping, as you know currently you are limited to ProPhoto, AdobeRGB, etc. For LR you have to export files to render into Joe’s spaces.
The chroma variants are for PS only, and boss cool. Here is a great overview from his website.
https://www.josephholmes.com/profiles/my-spaces-and-setsI hope the above helpful + all best,
Sean.