There are several “types” of Hypothesis annotations: Annotations
It is not consistent to distinguish different types of annotations (e.g., using "Annotation" as the general term) and at the same time to call a specific type with the same name. It mixes the general with the specific use.
I propose to use the term "Annotation" as the general term for all different kind of annotations. For the digital equivalent of a marginal note I would use "Marginal Note" as another name. (Just "Note" is not enough as it can't be differentiated from "Page Note".)