I can see this making personal budgeting more challenging, if you have many purchase mandates in-flight. Creating a budgeting system across manual and agentic systems is an open opportunity.

Worse, what about when you have a mandate that can be filled multiple times when you only need it once?

Why would it be an issue to have at-most-one semantics on this?

At most once payments have to be enforced via synchronization which makes the system much more complicated