One of the main excel advantages come from the fact that the app presents useful features and never changed their interface. Unlike modern software that try to change their workflow to "improve" it, excel has kept the same stable interface for decades. This allows people to create workflows built on the software, not fighting it. Excel users know that the interface they employ will be stable for another 20 years, or even more. Very few applications can say this, the other ones I know of including Vim and Emacs.
"Stable"? Like the version that screws up basic window management features? (Simulates the Alt+Tab behavior; doesn't actually let you have two Excel windows side-by-side.) Thanks, Office team.