Even though many mints offer certificates of authenticity with their bullion, do people really care that much? In my mind, COAs are meant to instill confidence. However, it seems that well known mint names and the reputation that follows them is what drives the trust. How much do COAs really matter?... after all, it's only paper.
Unless you go to sell the coin years down the road. Without the orginal box and papers the offered price is often substantially less than for the complete package.. even for coins many of would consider almost bullion pieces.
If your percentages are low.. just sort more. If your percentages are high.. just sort more.
Now selling Copper pennies. 1.6x plus shipping. Limited amounts available.
I agree with you Hoard. I can see wanting the box and any paper work that went with the coin just to complete the item as it was when originally purchased. If you're in the market for just the metal itself, then one shouldn't care.