Government issued gold and silver coins as 'legal tender' are a double edged sword.
On the one hand, I think you are right and they will always be more readily accepted than rounds or bars. This is true for Eagles, Buffaloes, Sovereigns, Britannias, Maples, Krugerrands, and Euros.
On the other hand, if they're legal tender, you generally don't really own the metal - the government owns it, and you are not allowed to melt them down. In other words, the government still has a say in it.