I think the annotation field should be shown whenever adding a new artist, label, place, …
Often at the point I add a new artist (mostly when adding a release) I have some information readily available that should go to the annotation. But because on creating a new entry, it is not an available field, I need to take care to add it later.
A lot of times, by the time I’m finished with all info for the release, I forget about it, or I already have closed the resources I opened to create the new entry.
Style is for non-code decisions. Adding a new relationship, changing a guideline, adding a medium format or a genre are the kind of things that belong there. Stuff that involves changing website code is Server (and if you have a doubt whether something involves changing code, don’t worry too much, we can always move it to the other project if needed).