I think edge-punched cards were primarily used for transaction and account data storage
with electronic accounting machines during the period when small and medium size
organizations were transitioning from completely manual accounting and record-keeping
systems to computerized ones. They were essentially a variation on things like mag-stripe
ledger cards used with the Burroughs Sensitronic and E-series accounting machines. I
remember seeing the edge-punch card equipment attached to a Burroughs TC-series machine in
the early 1970s.