Thought I would add my two sense to this discussion.
In my experience, I have found a lanyard to be a critical piece of equipment for ensuring my knives stayed with me during outdoor activities. For example, while I was going through the Evasion portion of USAF Survival School, I carried a Buck Crosslock in the front pocket of my BDU pants. Since we were covering a lot of ground during the day, including some low crawling, etc., having the knife secured with a paracord lanyard made sure the knife was there when I needed it. On another occasion when I was surf fishing in the Atlantic Ocean, I secured the knife with a piece of cord and drapped it around my neck.
On both occssions, making sure the knife stayed with me was my primary reason for using the lanyard. I have not tried to use a lanyard for quick draw and because I agree that it would probably just get in the way, will probably continue to only use a lanyard when I go "out in the field".
Dale H