Paper notes are still far more convenient to carry than coins and the US has far
more vending machines and cash register drawers than most other countries. While
many will accept dollar coins, the ones that do tend to be government owned (ie
Post Office) or located in casinos. The far more ubiqutous soda and candy
vending machines tend to take nickels, dime and quarters, and if you are really
lucky, the have a working receiver for $1 bills.

I think if you tried it, you'd find that most vending machines also
take dollar coins. At the time the government issued the SBA dollars,
the size was chosen in cooperation with the vending industry to make
modifications to machines easy. Then they found that the coins were
hard to tell from quarters, so now they're a different color and have
a smooth edge, but people still don't like them.

I gather the vending industry would be thrilled if we switched to
dollar coins, so they wouldn't need all those fragile bill acceptors.

Everyone in the US seems to think it would be awful if we didn't have
dollar bills, but everywhere else they've switched similar value notes
to coins, it hasn't been a big deal. What they really need to do at
the same time is get rid of pennies and round cash prices to 5c, both
to make room in cash drawers for the dollars, and because pennies are
worthless. We made do with pennies in 1947, and the value of a penny
then is about a dime now.

ObTransit: what coins do Metrocard machines take? They must take
dollar coins, since they return them as change. Do they take
pennies?

R's,
John