Those valuations don't really mean that much. It's simply number_of_coins * price. Saying it's worth $1bn does not mean you can take all of those coins and turn

Those valuations don't really mean that much. It's simply number_of_coins * price. Saying it's worth $1bn does not mean you can take all of those coins and turn them in for $1bn. If you owned a large portion of the coins and tried to liquidate them at that price, the price would quickly drop. The ICO funding model is new technology.