I always thought of it as a datastore. What else is it? A document with one or many tables, each containing rows of highly unstructured records (that can cross reference each other), but essentially it is a data store. Or is this view completely wrong?

There have been multiple points in my life where I’ve been tasked to create a plugin for excel for essentially this purpose.

It is a database though, one that is very accessible to most savvy people (aka, your domain experts) and you should lean on that instead of pushing them out. At least at smaller scales.

Is it at that point they should upgrade to Access!? (Only half-joking…)