Stimulus check update was set up by IRS to prevent duplicated stimulus checks. Below videos explains more into detail.
Understanding a Stimulus Check
Stimulus checks have been mailed out to U.S. taxpayers on several occasions. These checks vary in amount according to the taxpayer’s filing status. Joint taxpayers generally receive twice as much as those filing singly. In some instances, those who had unpaid back taxes saw their stimulus checks automatically applied to their outstanding balance.
Research posted on the National Bureau of Economic Research (NBER) found that the means of delivery of fiscal stimulus makes a difference to the overall spending patterns of consumers. Implementing fiscal stimulus by sending checks resulted in an increase in consumer spending activity. However, applying tax credits equal to the amount of money provided in a stimulus check did not result in an equivalent increase in consumer spending activity.