The feature is, I think, for people who want a music appliance (the Nucleus) and the minimum of user intervention - not for the likes of us with metadata OCD.
In the interests of experimentation, I bought a cheap USB drive, attached it to my ROCK/NUC and fed it a few CDs - a few single albums, and one with 2 CDs. Roon was able to identify all but one of the single albums. It failed to identify a new recording of Julius Eastman’s Femenine, bought direct from a boutique recording label. I used Roon to fill in the details:
Amusingly, when I tried this album with dBpoweramp, it claimed it was Die Meistersinger von Nürnberg, in a von Karajan recording…
Roon successfully identified the first disc on the 2-CD set, but it did create a second unidentified album for the second disc. A simple Album Merge, and the set was successfully identified and in the library.
So I think I’ll carry on using the USB drive. It might help wean me off from metadata OCD…