You make a valid point. But I've found that while dedicated vector tools are designed to make high fidelity artwork, their workflows are just not as quick for just putting down stuff on the page quickly.
Case in point, I hammered out 37 slides a few weeks ago in about 2 hours that captured a rough site layout, and a simulated workflow via internal hyperlinks. Maybe it's my unfamiliarity with the better vector tools, but I doubt that I could sit down in the morning and hash out a working sketch of a site before a working lunch meeting the same day in Inkscape. (though I'd definitely want to create some of the art assets in those tools for the final design).
Case in point, I hammered out 37 slides a few weeks ago in about 2 hours that captured a rough site layout, and a simulated workflow via internal hyperlinks. Maybe it's my unfamiliarity with the better vector tools, but I doubt that I could sit down in the morning and hash out a working sketch of a site before a working lunch meeting the same day in Inkscape. (though I'd definitely want to create some of the art assets in those tools for the final design).