I don't know how common this is, but I tend to do things like fix a specific recording or work (based on the information from official databases) which I would definitely want to be informed about if changes are made to it - but I don't know enough about the artist itself to subscribe to it, or I just can't cope with the amount of edits the artist gets. It would thus be much better for me to be able to subscribe to the specific recording or work instead of subscribing to the whole artist.