I cannot overstate just how much I love working on stuff in Excel and Google Sheets. It's the most popular programming language because it's incredibly intuitive to people at all levels of programming experience (especially the "none" level), it offers instant feedback, and in many cases, the results are trivially verifiable.

It does have its flaws, that you've pointed out - there's no good way to write tests, I'm not aware of any good way to have any sort of source control, and modularity is basically non-existent.

But, damn - if I have a bunch of data I need to go through and/or present, Sheets is usually my go-to. I genuinely love it when my spouse asks me to troubleshoot some Sheets stuff for her.