I guess knowing that you have only 3 minutes to assess someone anyway, you really can't expect to draw much more insight than just the looks & the initial vibe anyway. Plus there has to be an attitude that you go into a speed dating session -- there is a "way" to do it and its got to get tedious doing that intense 3 minute thingy with other people who do that and you can pretty much just pick out who you would or would not bang.
I guess to the above question -- the experiment itself is skewed because of the environment and the motivations that surround it. YOu can't really extrapolate those conclusions to "real life" and draw a massive generalization.