This sounds interesting.
There may be some confusion between POS transactions (typically used via a check-card, where the VISA network is the processor that actually verifies funds and authorizes a transaction) and POP transactions (The Point of Purchase ACH transaction, where the MICR data is read from the check, the check is returned to the customer, and an ACH transaction is created - however at no time are funds "verified", eliminating NSF or Closed Account items). You may want to search "Electronic Checks" in the THREADS section - there has been a lot of discussion about them.
Once a check is converted to an electronic transaction, it is covered by Reg E. Because this is now an ACH transaction, there is the 60-day return period for unauthorized transactions, using the ACH Affidavit of Unauthorized / Improper Entry. So, this is actually a little safer for banks.
The comments above are my own thoughts an opinions, not those of my employer.