Hi,

The @api.model_create_multi decorator is used to decorate the create() method in an Odoo model. This decorator is used when you want to create multiple records of the model at once. Without the decorator, the create() method can only create one record at a time.

The @api.model decorator is used to decorate methods that operate on the model level, not on the recordset level. This decorator is used for methods that do not need to access the current record, such as the _get_default_currency() method in your example.

In your code, both the create() and _get_default_currency() methods will work without the decorators. However, using the decorators can make your code more readable and maintainable.

Hope it helps

@api.model_create_multi : Create multiple records of a model in a single call and you can pass a list of dictionaries to create multiple records simultaneously.

@api.model : Create single record of a model.

Thanks & Regards,

David