Coins are smaller and are much more easily spent. And they last much longer than banknotes do too.
E.g. when I was in Florida I drove a few toll roads. The tolls were $1-$1.50. I couldn't spend my dollar bills on them, I had to scrounge up whatever random change I had lying around the car. Same with paying for parking. I couldn't feed bills to the parking meter. Again, I had to scrounge up whatever random change I had from the car.
I found it amusing that I could use them in just about any vending machine. Vending machines here typically don't have bill readers on them. After all, $5 or more for something out of a vending machine is a lot of money. I imagine a lot of the resistance to eliminating the dollar bill from circulation comes from vending machine operators, who had already gone to the expense of having bill readers fitted to their machines and wouldn't want to have to replace the coin mechanisms with ones that could sort dollar coins.
At the end of a given day I'd have a scrunched wad of dollar bills in my pocket that I couldn't really do anything with. I probably have about $100 worth of US cash somewhere at home, the stuff that went unused but wasn't worth converting back to Canadian dollars, and I'd wager almost half is comprised of one dollar bills.
The whole point of physical currency is to be exchanged for goods and services. One dollar can't buy you much. As a result of inflation it has in effect become pocket change... except not in the US. :/
(Similarly the penny should be eliminated altogether. They're so worthless you can't spend pennies on anything; in effect they have become demonetized.)
Bah. Say you're buying an item from a store. The cost is $8. You're paying with cash. What do you do?The whole world has been going green over our money for the last 50 years. Green is money. Money is green.
USA USA USA
You get out your wallet and sort through ALL of the bills in your wallet in order to find a ten, or a couple fives, or a twenty, or whatever. (Or you have created an excuse to rid yourself of some of the excess dollar bills you have, if you can find them.)
In Canada you open you wallet and grab a couple blue ones, or a purple one, or a green one. Or you use a blue one and pay for the other $3 with pocket change, since after all $3 is a pocket-change-size sum.
Just about every other currency in the world has bills which are different colours or different sizes in order to easily differentiate them. Only the US persists with keeping its money green. As inflation has risen most central banks have eliminated their lowest valued banknotes and replaced them with coins. Only the US persists with keeping banknotes with very little buying power.