"to avoid repeating it I'd put that inside another cell"

100%! I like to do that in other cases as well, just to keep formulae simple enough that someone else can easily audit the whole spreadsheet.

I'd rather have 5 extra columns in a calculation, then have a huge formula in a single column. This habit is so strong that I often do the same thing with Pandas: adding extra columns to a dataframe for intermediate calculations, when it would be better to write a larger function and .apply() it all at once.