Modern Commemoratives in the Stratosphere!!

I spent a great many hours looking at the other registered collectors of the Modern Commemorative Series. Many of the coins in this group are so rich with history and the Jamestown Series is just beautiful. I don't pay much attention to the value of the coins, as such, as I am more of a collector than anything else. I have been struck by the values listed for so many of these modern coins. They just can't be correct, can they? There is no way these coins would realize Numismedia assigned prices at auction; that being the case, I wonder what purpose that price guide serves, other than, perhaps, insuring value. I also note that five or so of the coins in my collection have no price/value assigned to them. The whole things seems a mystery to me. I would love to hear opinions of other collectors regarding Numismedia, selling/buying prices, and just what, if any, those assigned values have to REALITY!