I don't know if it's still the case, but when I was an undergrad a professor pointed out that Excel's Gaussian tail probabilities disagreed with everything else (Mathematica, Matlab, R, etc.) for large values.

The financial industry uses a lot of Excel too.

Yeah but usually not as the system of record/origin for any data. Mostly for consuming data from elsewhere, and often in conjunction with various plugins (some of which can allow Excel to act as the "front end" to a production server that actually crunches/stores the numbers).