Why is tab unaffected by font whereas space is affected?

[Sławomir Osipiuk]

On Mon, Apr 20, 2020 at 10:39 AM Eli Zaretskii via Unicode
<unicode at unicode.org> wrote:
>
> That would mean, for example, that if you make the font smaller, the
> tab stops stay in the same positions, pixel-wise?  isn't that strange?

I don't think it's strange to define a tab position as a fraction of a
line, rather than a number of (font-dependent) space widths. Both
approaches have advantages and disadvantages.