[ineedasername]

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.