Excel supports a variety of data types other than numbers and includes many built in functions for dealing with non-numeric data. Whatever it's history, it is not accurate to say that it is only for numbers.
Regardless of its _additional_ support for other types, those are only in support of its primary role as a spreadsheet. It is designed around the concept of plugging in _numbers_ and calculating with them. Everything else is to make those calculations well notated and human friendly.
Any other use of Excel is bending it into a role it wasn't intended for, and user beware.
And it is all too easy to just go there since there are soooo many convenience features for those who don't want to laern how to do the tasks well.
If notation were the sole purpose there'd be little need for anything but row and column labels or simple string input. Instead there's a full set of string manipulation tools, embedding of other objects, charts, images, drawings etc.
You are taking the application as it existed 35 years ago and saying it must still be that thing, yet it has had 35 years to evolve far beyond that. Microsoft itself, when it talks about Excel, talks about using it to organize "data", not just numerics data. It has become a more general purpose tool.
Any other use of Excel is bending it into a role it wasn't intended for, and user beware.
And it is all too easy to just go there since there are soooo many convenience features for those who don't want to laern how to do the tasks well.