Because billing needs something to bill against, and the easiest way to get it is to copy patient detail into the finance system. It works, and it creates a second store of sensitive data with different permissions and no clinical governance.
The alternative is usually a spreadsheet, which is worse in every respect.
The financial record references the episode rather than holding its content, and field-level permissions mean finance sees what it must and nothing more. Every access to a restricted field is recorded permanently.
Contracted and private income sit on one ledger with their own terms, so payer mix is a report rather than an exercise.
It does not code procedures, submit claims or price against a tariff schedule. It is the ledger beside the systems that do.
And it does not make you compliant. It provides field-level control and an uneditable audit trail; the configuration and the lawful basis are yours.
Consumables and stock are costed where they are used, through inventory and cost centres, so the cost of a service line is real rather than apportioned annually.
Fixed assets and depreciation cover equipment on the same books, and payroll postings from Nest land there too.
Products, not integrations. Each one reads the same record, so a join is a permission rather than a sync job with a mapping screen behind it.
No, by design. It references the episode; permissions are per field.
Yes, contracted and private income on one ledger with their own terms.
Yes, through inventory and cost centres.
Half an hour on your own numbers is usually enough to say whether Books is the right place to start.