Well, given that small denomination paper money bills have a very short lifetime and a coin has a lifetime of 30-50 yrs, it is cheaper to have coins (UK did it, and EU too)than paper bills in small denominations. The only problem is how to make the coins acceptable. Maybe it should be Reagan coin.
It will. Didn't you read the article? The coins will have portraits of all US presidents. In order.
And to re-tool machines to accept these. I remember the Susan B. and the only machines where I lived at the time that would take them were the turnstiles for the Miami Metromover. And mostly people just collected them. Maybe they can make them the size of silver dollars.
I would like $1, $5 and $10 coins!
If they had done something like they are doing with the quarter, having all of the states on them, the dollar coin would have been a smash hit.