Agreed... but see my Lisp example in https://news.ycombinator.com/item?id=49593406 for a place where tabs end up unavoidably ambiguous. Because in that `cond` example the tabs look like they're used for indentation, but they're actually being used for alignment, something that falls more under typesetting than under indentation. A smart editor that has read the Lisp code (note that I'm using "read" in its Lisp meaning, i.e. "parsed into a syntax tree") can make those tab characters correctly align the forms the way you'd want them to be aligned for maximum understanding... but really, you would want space characters, not tab characters, in that context.
So even though in most cases those three uses for tabs are independent, in some languages they get muddled. F# is another language where you may want to align text on line two with the middle of line one, e.g. if you write
let person = { FirstName = "Bill"
LastName = "Gates" }
Now, that's considered bad style according to https://learn.microsoft.com/en-us/dotnet/fsharp/style-guide/... — and they're entirely write to recommend against that style — but it's legal syntax. And it's probably why https://learn.microsoft.com/en-us/dotnet/fsharp/style-guide/... forbids tab characters entirely in F# code.(Those two links point to different anchors in the same document, BTW: the HN link shortening is going to make them look identical until you hover over them).
The cond example commits a sin (see my other reply), in the F# example tabs (were they permitted) would introduce no ambiguity if used solely to communicate indentation, and the only change I would make to the F# example were I formatting it myself would be to also align the `=` characters. Actually that supposedly bad style is more or less exactly how I write nix expressions (as a matter of practicality I do not use tabs when writing those FWIW).