Manages multiple sub-models. For example, a user model might have an addresses object list to model multiple user addresses. Therefore, when you query a user object, you also automatically get the addresses list of the queried user.
Object list fields are tightly coupled with their parent model, meaning when a parent model object is deleted, then the sub-model objects are also deleted. If you think the number of sub-model objects is limited (e.g., in tens or hundreds), then you can use an object-list field to model these cases. However, if you think the number of sub-model objects does not have any limits (e.g., thousands, millions), it is recommended to use a separate model to handle these cases.