But regarding your conclusion; my entire point is that it IS more useful than you might think. Disclaimer: I often use emacs e g regex-replace and other means of code generation as well, both a couple of internal dsls that I've built and directly one-off by programming (normally clojure).
To just expand on the code generation part: The fact that it is a large "cell based" structure means that I can move stuff around manually, quickly see the entire new structure, make overrides and so on. If I have some class that's supposed to match a csv with 80 fields, it's really hard to view that in any good way in source code.
I won't argue this with anyone, I realize many people vehemently hate spreadsheets, and Excel in particular, and disagrees with anything positive said about them. I'll just end with two final points.
1. The spreadsheet is a general purpose functional programming language with very large adoption and pretty much unseen "code editing" tools (outside of emacs), such as duplicate removal, sorting, user editable conditional formatting, and so on.
2. This was a tips on a tool to have in one's arsenal that is often overlooked, I wasn't looking for a debate.
Excel. Seriously. For more things than you imagine
Let's say you want to make a property assignment for some class;
this.a=x.a
this.b=x.b
...
While you probably would want to do this some other way to start with, and while you of course can solve it using some emacs wizardry, I can whip that up in Excel using some formulas in a matter of a minute. Moreover, I can keep adding to it when I realize something was missing.
I can make a diff, join or union of the results of two queries from different databases (or even database engines). Not to mention calculation and design mockups.