“Nonetheless, many financial systems do have availability which is far closer to five twos.”
Google Search would call five nines a disaster. Your bank runs at five twos and closes on weekends, holidays and whatever day a Japanese counterparty says its company was founded. Black Friday lands the biggest predictable payment surge of the year in the middle of a four day stretch when money is not moving. The app in your pocket is fast. The money behind it keeps banker’s hours.