Have they not heard of the invention of plastic? Nice, slim, shiny, fast! FAST! I spell it for you, indian: F-A-S-T!
It does not delay the life of everyone else waiting in line behind you!
It is easier to keep track of what you spend!
It avoids (that's right!!! Avoids!) painful and useless trips to that ancient meeting place called "the bank"!
Off the top of my head, there you are! 3 advantages for replacing your cash usage for credit card usage.
DO IT!!!!!!! And stop making everyone in line mad as you count your freaking pennies at the register!