Is Excel compulsory? Surely it's not the only spreadsheet application on the planet?!

No, but it is ubiquitous. It is not just scientists that use it. Journalists, statisticians, governments, politicians (who are anything you want, but not tech savvy!).

And who would think when importing 1000 lines from, say, a CSV, to check each line and column? Especially if you didn't know the problem existed.

And with increasing dependence on personalised (gene) therapies - this is life threatening.

Remember the Y2K problem? People blamed the computers, but it was mostly a legacy for when people understood the shorthand for dates. Which predated computers. Like 102 year-olds getting medication for 2 year-olds. When the 102 year-olds were 2 years old there were precious few 102 year-olds. Needs change!