I agree, but perhaps the guidelines at Disambiguation Comment - MusicBrainz should be updated to explicitly mention this as a valid use of disambiguation comments. Right now, the page just says:
Disambiguation comments are used to distinguish identically or similarly named artists, labels and other entities. They are visible on entity pages, as well as in search results.
I think that something like this might work:
Disambiguation comments can also be used to provide well-known-but-unofficial names for self-titled or untitled release groups.
In addition to the examples that @IvanDobsky gave above, there’s also
Metallica (“The Black Album”).
(A cleaner approach might be to add an “alternate name” alias type and display those aliases alongside disambiguation comments throughout the UI, but I can say from recent first-hand experience that that would be a lot of work.)