Venmo is an app that makes paying people fun. When you pay a friend to split dinner or something, you can celebrate the payment. Many people have a list of friends that is public. Even when they shouldn't. For example, members of Congress and many Trump administration officials and nominees.
It took Mark Alfred, who is basically a student intern at Notus, 5 minutes to locate a dozen members of Congress on Venmo. Then, in a few more days, he tracked down 50 current lawmakers, 20 former members of Congress, and over three dozen current members of the Executive Branch. Among the many people Alfred found were Transportation Secretary Sean Duffy, trade adviser Peter Navarro, U.S. Attorney for NJ Alina Habba, Stephen Miller, and Karoline Leavitt.
This is not good. First, a public list of Venmo friends and transactions could expose more of your private life than is wise for a public official. For example, Rep. Steve Womack (R-AR) uses Venmo to pay off losing bets, which he called "donations." A lot. Does he really want his constituents and others to know he has a gambling habit? Rep. Jen Kiggans (R-VA) paid her housekeeper—and gave her full name and address. Maybe not a great idea, especially if the housekeeper was not in the country legally.
Another problem is that a criminal who collected a list of people a representative knows could try to use that for blackmail or make a spearphishing attempt to scam the representative by making a request look like it came from a friend. And beyond the shady stuff, does a member of Congress want everyone to know that some lobbyist is his or her friend? Also, some of the friends were reporters. When some reporter has a scoop from an "anonymous source," knowing whose Venmo list(s) the reporter is on may make it easier to determine the source of the scoop.
All this raises the question of whether people who aren't even able to protect their own security are able to defend national security. (V)