Read the amount and invoice number from 4,000 incoming invoices — all in the same format from the same supplier.
Same format means fixed position. A few rules read that identically every time, cost nothing once written, and never get it wrong. A model would be slower, dearer and occasionally creative.
Read the same fields from 4,000 invoices coming from 300 different suppliers.
Now it tips. Describing 300 layouts by hand is a life's work, and supplier 301 starts it over. This is exactly what a model is built for: finding known things in unknown places.
Check whether an entered IBAN is valid.
An IBAN carries its own check digits. The arithmetic is in a standard, fits in ten lines and is provably correct. A model could only be worse here — guessing where you can calculate.
Work out the recurring complaints across a thousand pieces of customer feedback.
The same complaint appears a thousand different ways: “too slow”, “waited forever”, “nothing happened”. Searching for keywords finds the words, not the theme. Summarising meaning is a model's strength.
Calculate a shipping price from weight, zone and customer group.
A table and three conditions. The result must be right to the cent and defensible in every case — in court as much as in accounting. A model that is occasionally a cent out is useless here.
Route incoming email to the right department when senders write freely.
“My invoice is wrong” belongs to accounting, “can't get the app open” to support — without either sentence saying so. Recognising intent where no keyword helps is worth a model.