I beleive it was in Aikido Shugyo: Harmony in Confrontation where I read that the purpose of wrist grab attacks such as Katatedori are to simulate punching attacks.
Shioda Gozo Sensei says (I'm paraphrasing)that these attacks mirror the movement, timing and balance of a punching attack, but take the fear out for beginners.
Therefore, I answered "NO" to the poll question, because Katatedori is only meant to simulate an attack for the prupose of learning basic movement, not be an actual effective attack in and of itself.
P.S. If you haven't read it yet, Shioda Sensei's book is very interesting, more for the ancedotes and autobiographical stuff.