I tend to agree with this. I like operator overloading for mathematical constructs (like complex numbers or even just for conversions of literal types, Imagine, for example, you have a gram type and a second type, if you said 1g / 1s you'd get 1gps, that seems reasonable)

I don't like it in the example given

    for (int i : std::views::iota(0, 6)
               | std::views::filter(even)
               | std::views::transform(square))

What benefit does this have over the Javay/Rusty version that looks like this

    for (int i : std::views::iota(0, 6)
               .filter(even)
               .transform(square))

?

No deducing what `|` means, you are applying the filter then transform function against the view.