So, if I back a truck up full of pennies, everyone's cool with that, right?
Of course, I keed, but I would LOOOOVE to see the look on a provider's face if a guy rolled up in a truck, with that backing up 'beep, beep', and started dumping a ton of pennies all over the place.
He jumps out of the truck, smelling like copper, and says, "I counted them six times. They're all there."
But in all seriousness, I prefer to lay a couple three big bills and make it visually easier to count rather than dole out a bunch of small bills. But the big bills aren't always available unless you make direct withdrawals from your own bank. Some ATM's give them out, but not all. When you're on the fly, sometimes you just gotta go with those 20's.
I've bought something from Walmart before and got 100 in cash back (max they'll go), and the thing spit out a bunch of 10's. Even had to deal with a bunch of 5's a few times.