To me it doesn’t seem to speak at all to “how good” anybody is, just to the nature of the work the job demands.
A fine artist will paint a better portrait, but they might not be the right hire to get a housing development painted and shipped (so to speak).
The fine artist may be less good at house painting than the tradesman, the tradesman may be less good at portraiture than the fine artist.
There’s always the possibility that somebody could be good at both, but they’re orthogonal: both dip something in paint, but that’s where the similarities end.