Now? I use credit cards almost exclusively and I if I get $100 in cash out of an atm, I regularly go a couple months or more without having to get more cash.
Definitely useful and I go through 100 every week or two
When I was younger I used to pay in odd amounts in order to maximize the number of quarters I got back in change; I'm sure that would just confuse people now.
That said I think everything below the quarter is useless and just adds a ton to cash handling difficulty and expense. It'd be sad to see them go as they were/are staples of currency in the US, but functionally their purpose is so seemingly useless.