99% of uses can be trivially replaced by plain text, Markdown, or Org. For the others you probably want a real typesetting system anyway, so Word would still not be appropriate.
> Excel
If you're at a point where it feels appropriate to use vendor-specific spreadsheet features then you have already outgrown by far spreadsheets. It's probably both simpler and more maintainable to decouple your data from your code by using a database (even SQLite, if you still want to pass files around) and/or a scripting language instead.