What is a checking account and how does it work?
A savings account and a checking account (or a "demand" account, or a "transactional" account) have different regulations.  For example, fractional reserve requirements are 10% against checking accounts, but 0% against savings accounts.  The theory is that savings accounts are sticky, while checking accounts are hot money. So the Fed wants to stop banks from creating accounts that are regulated as savings accounts but have the features of checking accounts.  In the past, this was done by forbidding banks to pay interest on checking accounts.  They eliminated that rule back in the inflation years, and instead imposed the rule that to qualify as a savings accounts for regulatory purposes, banks must discourage you from using them as transactional accounts.  For example, by limiting the number of withdrawals per month that can be made from a savings account. If the Fed gave up on trying to enforce a distinction, I suspect there would soon no longer be a distinction.