When a shared ledger beats a shared database
Most companies already share data through email, portals or EDI links. A blockchain is worth the extra complexity only when three things are true. Several independent organisations write to the same record. They do not fully trust one another, or none of them is willing to let a rival host the system. And the history of changes matters as much as the current state.
Supply chains fit well. A pharmaceutical or food batch passes through a manufacturer, a distributor, a cold-chain carrier and a retailer, and each hand-off needs a record nobody can adjust later. Trade finance fits too, where a bill of lading, an invoice and a payment instruction must agree. Property transactions that involve developers, banks, brokers and registries have the same shape.
If only one company writes the data, a normal database is cheaper and better. We say so when that is the case. Part of the discovery stage is a candid test of whether you need a ledger at all, and we would rather lose a project than build something a spreadsheet and an API could do.
