So by eliminating the penny and nickel, we can make dollar coins the size of a nickel and every vending machine will take it!
Lots already do take the existing quarter sized dollar coins, between color and weight differences they’re pretty easy to mechanically differentiate. Apparently the vending lobby thinks big coins are bad, I’ve never figured out their excuse. But with pennies and nickles out of the mix resizing could “fix” a lot, leave dimes or make them penny sized, shrink quarters to nickle sized, and then the dollar coin is a unique size and less annoying to users. Of course they’re still not as convenient foldable paper so we still won’t convert.