There is often an uncomfortably long delay between payment and voucher redemption

The workflow for voucher redemption often goes something like this:

1. User generates a random voucher
2. User inserts the voucher into ZKAPAuthorizer
3. ZKAPAuthorizer tries to redeem the voucher and receives an unpaid failure
4. User finishes the manual payment process
5. Time passes
6. ZKAPAuthorizer tries to redeem the voucher and receives a successful response

The duration of (5) tends to be almost 3 minutes because (3) and (4) often happen quite close together and ZKAPAuthorizer waits 3 minutes between redemption attempts.

Since these 3 minutes happen between the time when the user believes they have remitted payment and the time when they receive their ZKAPs this can be an anxious time.