All this functional talk annoys me. For example, I want to get strong. Progressively lifting more weights on the deadlift gets me stronger. Sounds functional to me.
Definition of function according to the oxford dictionary, "An activity that is natural to or the purpose of a person or thing".
If your goal was to lift something odd that creates a moment arm, the deadlift might not be the most ideal exercise. That being said, I'm sure it still helps to be able to deadlift a shit ton. So is it still functional? Yes, it's functional in the sense that it gets you stronger hence increasing the chances of you lifting something odd.
I'm going to argue that pretty much everything is functional to a degree. Let me steal a page out of @T3hPwnisher's book.
If your goal were to be stronger, this is in fact functional. The guy who squats 135lbs on a bosu ball is stronger than the guy who doesn't squat, that being said, I'm not advocating squatting on bosu balls. It functions as a way to get stronger albeit a stupid way that'll probably end up hurting you.
Everything is 'functional' but not everything is effective.