Plus, Venmo (and PayPal) has interest in being a trusted brand in financial transactions of other sorts, I'm sure. PayPal has a credit product now, for example. I would not be surprised if they have a rent-seeking lobbying interest in making federal bank transactions remain a worse experience than their own service.
[0]:https://www.marketplace.org/2018/02/20/what-are-apps-venmo-d...
Inertia, at least partially.
It's why chip-and-pin is still not a thing in many places: Old School credit card POS devices were distributed to a lot of places over the years, and those only had the magnetic strip readers. Replacing is time consuming and no one wants to go through the expense and effort of changing it in all the places that they're in (e.g., gas pumps).
Sometimes it's handy to be a late/delayed adopter of technology and to skip a generation or two.
Chip-cards replaced old cards here in 2006. During those 14 years every reader has already been updated several times, including gas pumps.
So it seems somehow the US has a much lower rate of updating readers - I'd really like to know why that is... Maybe the merchant services market is somehow radically different?
Because, as pointed out in other comments, the United States pioneered electronic finances when the rest of the world's banks were still settling their accounts at the end of the day by dragging cartloads of paper money and gold bars from branch to branch.
You're welcome.