My take:

The Oval Office isn’t like Trump Tower, it’s not a corporate entity.  Those who work, even at the pleasure of a president, in the West Wing, are paid by taxpayers.  As even in these times, taxpayers still have a fundamental right to know where and how their money is spent.   No, we’re not talking about classified information, it’s just the opposite.  America actually does have a need to know the state of president.

Once the unconstitutional practice was out in the open, the White House filed an arbitration case against Manigault over breaching the NDA, which has little chance of winning even in a one-sided arbitration proceeding. To point out how pointless NDAs are, First Amendment lawyer Mark Zaid wrote on Twitter that NDAs are so unenforceable he would “represent pro bono any Trump official who was made to sign one.”

Source: These White House NDAs Are Crap—These People Work for Us, Not Trump