POS is transaction-focused
Its central job is to create and complete a sale quickly.
ERP is cross-functional
It connects the sale with purchasing, supplier history, stock movement, payments and management reporting.
Omnichannel businesses may need both
Physical retail and online commerce can share product and inventory records while using different selling interfaces.
Avoid separate stock masters
If POS and ERP maintain independent product and stock truth, reconciliation becomes difficult.
Decide where pricing rules live
Discounts, customer groups and taxes should have clear ownership.
Choose based on operating complexity
A small counter sale operation and a multi-warehouse eCommerce brand do not need the same system depth.
The operating principle
Every event should remain connected to the product, contact or transaction that created it. That is what lets ERP explain a number instead of only displaying it.