Excellent article, well researched and helpful to all who have eyes to see and ears to hear. In my lifetime (pre 1964) in the US we could exchange dollars for silver dollars at major banks in larger cities. Few people did so, myself included.
Then too, any bank would give you $1.25 for every dollar's worth of Silver Certificate including $10 and $20 bills. My father had a stack of them in a wall-safe, which I bought at face value and even sold a couple to the bank. However the balance eventually got so moldy sitting in the safe for so many years that I was lucky to finally get face value many years later. (Condition counts for almost everything with collectibles)
Here in Miami, even Gold Certificates still come in from Cuba and other Latin American countries and people exchange them unknowingly for face value. Depending on condition, the coin dealers would give them a much sweeter deal.