Although the main argument of the linked article on why it's more expensive, is that people tend to hold on to coins (put them in useless jars) rather than use them, so the government had to produce 1.6 dollar coins for each 1$ paper billed replaced.
In the linked PDF file , search for "1.6", you will find this sentence in the same paragraph:
"However, in both cases, once the transition was complete, coin
production was very low or even nil in some years. Therefore, we
determined that a 1.5-to-1 replacement rate would be appropriate for our analysisâ"low enough to avoid an excess of $1 coins without creating an undue risk of producing too few."
It was only a transition issue, there is no mention about people forgetting about those coins in jars. A 1$ coin is useful, it's what is usually given as a tip for a beer in a pub, so I find the argument that people put them in jars kind of odd..