A showcase presents you. A store carries the sale: find, cart, pay, stock, status. One is a message. The other is an operation.
Where the sale is lost
The customer finds the product, payment stalls, the order drops into WhatsApp, stock is wrong. A beautiful page does not cover that gap — it raises the expectation.
If a catalog and one form still suffice, a small site is right. If orders are daily, the chain should live in one place.