Django's ORM has a Model class that wraps an underlying SQL table to can runs queries in an object-oriented approach. When using utility methods like .filter()

Django's ORM has a Model class that wraps an underlying SQL table to can runs queries in an object-oriented approach. When using utility methods like .filter() and .annotate(), you're executing them against the Model (well a ModelManager to be more specific) so they inherently understand the model (and thus the underlying table) that you're querying against. This allows Django to translate the arguments you pass into those methods into SQL, while also handle SQL parameterization, etc. If the ORM were to allow you do build a raw query, using multiple tables, views, nested queries, etc - it would be difficult for it to then allow those utility methods. The ORM wouldn't have the Model class and it's associated fields to use in while translating the method's args into SQL.