Pen and paper interviews would almost certainly be more accurate. The problem being that images of people writing on paper are especially un-cinematic. The participants were encouraged to take as much time as they needed, many of which took several minutes before responding on some questions. However, the majority of them were concerned with how much time the interview would take up, and their quick responses were self imposed.

Whether the evidence is too messy to draw firm conclusions from, I agree that it is. This is an inherent problem with documentaries. Omissions of fact are easily justified. Also, just like in fiction films, a higher degree of manipulation over the audience is more sought after than accuracy.