As you say; billing system is tip of an iceberg. There's reconciliation, settlement, payouts, tax, financial reporting and what not. For a small mom-and-pop sto

As you say; billing system is tip of an iceberg. There's reconciliation, settlement, payouts, tax, financial reporting and what not. For a small mom-and-pop store, sure build it. But for any half-complex business billing is a rabbit hole.