I think that these HR tests basically ensure uniformity of candidates to a certain extent. But if all people in a workplace are of the same nature, if they wear the same clothes (some companies require that too), and if they think in the same manner, a lot of out-of-the-box thinkers would be left out. And it is a law of nature that the higher the variety, the better the yield. I believe that a lot of differently thinking people can generate great ideas by mutual interaction.
By the way, that's exactly why I left a corporate career at a bank: I was the only person in the entire floor to question the dress code, I was the only person in a 10.000 people center to commute by bike (among other things) and I got tired of being the ugly duck and having my ideas being completely rejected just because they were different.
