Just a couple of weeks ago I saw a video of a guy who got internally decapitated by the barbell during a high bar squat because he leaned forward and came up onto his toes rather than sitting back.
That's a freak accident, and it's certainly turned out that stuff like deadlift hyperextension is not nearly as dangerous as originally thought, but "form" also means "keeping the bar path under control and in a safe range".
Just because most people have figured that out before they graduate to handling potentially dangerous weights doesn't mean it's not still a critical piece of the safety equation.
