Does anybody else find it ironic that pg uses an abnormally high amount of filler words himself?
Obviously someone with a solid business plan who speaks cautiously is in a much better position than a smooth talker who is selling vaporware. That's the value of the YC group, they have their priorities determined and they don't get taken for a ride.
For must formal presentations the audience expect clear and concise responses. One should be forgiven for "filling" during a public speech or informal chat.