A core banking system captures and stores all the transactions and business a bank performs. Without this a bank would not be able to function let alone produce a meaningful financial report.
In what way does that mean you'd be able to disprove the statement:
"In financial reporting you have a lot of situations where you need a consistent point-in-time snapshot of your data or you might be in very big trouble."
You're trying to sell your anecdotal experience rather than explain your point.
