The scale of health insurance claims is incredible, my company has a process that simply identifies when car insurance should pay the bill instead of medicaid/medicare post traffic accident (subrogation). Seems a minor thing right? We process right at 1 billion a year in related claims (and I don't know our US market share, maybe like 10-20%).
I am guessing every datascientist that works for a BlueCross BlueShield at individual states deals with processes that touch multiple-million dollars of claims.
We even now have various dueling systems -- one company has a model to tack on more diagnoses to push up the bill, another has a process to identify that upcoding. One company has models to auto accept/deny claims, another has an automatic prior authorization process to try to usurp that later denial stage, etc.