There are plenty of explanations that don't involve living paycheck-to-paycheck.

1. You keep money in several accounts (checking, savings, money market, paypal, etc.)

2. You are a contract worker being paid in large installments and you need to know whether your deposit has cleared before paying bills.

3. You have difficulty with fiscal discipline and only leave money for essentials in your account to prevent over-spending.

and so forth.