I agree that the scores don't have to be high, but an exceptionally low score can be indicative of other problems that could translate to issues on the field. Things like general awareness, ability to assess game situations (do I run this kick back or fair catch it?), judgment off the field and quality of the company you may keep.
It's not everything, but a team investing in a player with a red flag like this should take some extra steps to reduce their risk.