Clean books tell you what already happened. They do not tell you what to do next. That translation, from accounting output into a forward-looking model, is where most of the value sits.
The difference is structural. Bookkeeping records transactions; a model connects them, so net income flows through to cash and to the balance sheet at the same time, and you can see the effect of a decision before you make it. What separates a useful model from a fragile one is driver-based planning: revenue built from sales capacity, quota attainment, conversion, churn, and pricing rather than a single number that grows by a percentage.
Inadequate visibility into cash is associated with 38 percent of startup failures, and most of it is foreseeable in a model built this way.