Work is hard. Training shouldn't be.
There is no substitute for a technical animation to explain complex ideas in minutes. Not the best sales staff, not even actual video, and definitely not words and pictures. A strong technical animation is by far the most efficient way to teach a concept to an audience in two minutes flat.
It's better than video. How do you teach the principles of an internal combustion engine using just video?
It's better than pictures or text: How do you show all the dynamic relationships among moving parts?
It's better than voice: How do you explain the same combustion engine using just voice and hand gestures? Don't put people through that.