While Grid(I love named areas!) and Flexbox have improved layout, the initial layout process is still rougher than it should be.
Pretty much every other design/layout/ui creation tool has all kind of helpers which pure CSS lacks.
I am talking about basic guidelines, rulers etc that every tool/layout under the sun (QT, WPF, WinForms, Photoshop, Illustrator even Powerpoint, you name it the basic alignment rearrangement functions are a mouseclick away.
Sure the created document might be a huge mess, but that is not the point when you are messing around.
If you start messing around with CSS you enter a world of pain unless you know the properties down cold.
Client asks how would that picture look here and that menu shrunk a bit down here?
With CSS it would take much longer to iterate than with any other tool.
With something like WPF I do not need to know XAML by heart to quickly create some reasonable working mockups for a .net application.
This explains why it is much easier to do creative mockups in another tool (I see designers who use Adobe XD quite a bit now).
When one is in the creative stage CSS is a huge hindrance.
It depends on what a "mockup" is.
In sane web development, done by a web designer with HTML and CSS (not by a graphic designer with Photoshop), a mockup is a web page with mock content and incomplete stylesheets.
While Grid(I love named areas!) and Flexbox have improved layout, the initial layout process is still rougher than it should be.
Pretty much every other design/layout/ui creation tool has all kind of helpers which pure CSS lacks.
I am talking about basic guidelines, rulers etc that every tool/layout under the sun (QT, WPF, WinForms, Photoshop, Illustrator even Powerpoint, you name it the basic alignment rearrangement functions are a mouseclick away.
Sure the created document might be a huge mess, but that is not the point when you are messing around.
If you start messing around with CSS you enter a world of pain unless you know the properties down cold.
Client asks how would that picture look here and that menu shrunk a bit down here?
With CSS it would take much longer to iterate than with any other tool.
With something like WPF I do not need to know XAML by heart to quickly create some reasonable working mockups for a .net application.
This explains why it is much easier to do creative mockups in another tool (I see designers who use Adobe XD quite a bit now).
When one is in the creative stage CSS is a huge hindrance.