I love the dollar bill. I'd really love to have a £1 and/or £2 note in the UK. The moment you need any reasonable number of coins to buy anything they become unwieldy in your pocket and you can carry enough dollar bills to be useful without there being a chunk of metal digging into your leg.
I've hears arguments against relating to durability but those are all predate the new plastic notes we have.
For some reason I get a load of pushback when suggesting that a £1 or £2 note would be nice to have.