How to Answer
The answer is, you probably use both methods for counting cash. If you have handled money as the teller before, the odds are that you have utilized both. Many financial institutions have cash machines that even dispense the correct withdrawal amount for the customer, so you never touch the cash.
The interviewer wants to know what experience you have to ensure they provide you with the best training possible if you are selected for the job.
Entry Level Example
"Because I am new to my career as a teller, I have not yet used a counting machine. I am great with quickly counting cash by hand from my years of experience doing cash-outs in the pub I worked for."