If privacy is an explicit goal, why isn't it a MUST? Why even bother with the initial batch issuance phase? And what's stopping them from silently adopting a batch size of 1?

> Why even bother with the initial batch issuance phase?

This is a solution that requires non-trivial interaction between many paries.

It seems very reasonable to want to get the parties started on the implementation so they can iron out issues in the infrastructure they're building while they work on the details of the ZKP aspects.