I think this is a good read to learn about what tabs and tabstops really are regardless of whether you agree that tabstops should be at different positions per line or with the controversial idea of using proportional fonts (this would work with monospaced fonts too).
Yeah, I personally don’t like aligning key value pairs all the time (maybe rarely I do). The most compelling example is putting a tab before end-of-line comments. Also it would make tab delimited CSV files render more easily.
To me it feels like this would work nicely for something that’s more tabular in nature, such as you mentioned, CSVs. But again, not all the time, which makes this formatting hard to use.