That's because they're exactly what a competent finance person needs for conversational analysis. Spreadsheets have their place but if you cannot talk without a keyboard you are way too deep in the numbers. And the batteries never die, at 3am on day 3 of due diligence in Toledo your phone and its finance app will be dead but that 12C will still be cranking out present values, amort schedules, target return rates and IRR. Those calculators are maybe the most fit-for-purpose white collar tool I've ever seen.

EDIT: I don't care for MSFT, I loathe Word. But Excel on Windows is a genuinely fine tool -- overused by a lot of people b/c the Windows anti-pattern keeps them from proper tools, but still a really useful piece of work. You can't do detailed modern financial analysis without it. The alternatives -- Linux, Google Docs, even Excel on Mac -- aren't even close.