From Washington Examiner:

“The move is mostly symbolic because local mask mandates are already in effect in most places. However, President Biden wants to show he is taking the pandemic seriously, and enacting a federal mask mandate supports that position,” said Ashley Nunes, director of competition policy at the R Street Institute.

“There is conflicting data about the extent to which such mandates help because the policy is often accompanied by other measures, like physical distancing and limits on gatherings,” he added.