Akihiro commented, on August 20, 2012 at 8 p.m.:

Thanks for the comment Luke atoblusely correct, but I disagree. The documentation and tutorials all lead someone new to Django to use the AddManipulators (and ChangeManipulators) and rightfully so. They're great tools that do a HUGE amount of work on your behalf. I love using them, and I think that the default behavior should be different than it is.You can also create objects directly and in those cases you're back to doing all the form validation and verification type activities yourself. You can loose quite a bit when doing it manually especially when that data is coming from a web form.