And that's just consumer banking. There's also commercial banking. Most businesses still take in lots of cash, and need to send an employee to their bank to deposit it on a daily basis, since having lots of cash in the store encourages robberies. (If you're a large store, you'll use an armored truck service to move cash, but a pizza shop probably doesn't.) This requires teller services, since depositing thousands of dollars in cash via an ATM would be cumbersome.

Thus, neighborhoods with lots of retail businesses also need enough bank branches to support these businesses.