Welcome to the mid 1980s.
Australia has had $1 and $2 coins and plastic notes for $5, $10, $20, $50 and $100 for about 20 years now.
All the notes are of a differant size and colour too, so it is pretty much impossible to mistake one note for another, and they are waterproof, no more finding $150 worth of soggy paper in your jeans pocket after going through the wash, or in the boardshorts after a quick swim. Virtually impossible to counterfeit too.
A couple of years after you guys change over(once the whole 'newfangledness' has worn off) , you will wonder why the US didnt do it years earlier.