Why do you bring this up? Is this more ideal? I thought writing inline css was an accepted awful thing to do. Or is that just a simplification for new developers? Why do you benefit from doing this?
Why use inline CSS? Because it's simpler and obvious. The proposed hack has no upsides: it isn't any more accessible, isn't any more maintainable, and it isn't any more performant (quite the opposite).
To me it's in the same category as replacing `<font color=red>` with `<span class=red>`, because "font is bad".
The CSS is ugly because of the many redundant rules. But if you have x bar charts on y pages, then one ugly CSS file is better than x repeated ugly spots spread out in y HTML files.
Also it's very unlikely you'd have many charts with markup written by hand. I'd expect charts to be generated from a template from a proper data source, so change in markup of all charts would still be done in one place.
GP is saying that there is next to no benefit to the approach proposed in this project compared to just using [the ugly and terrible] inline CSS.
<div class="bar-chart">
<ul class="container">
<li data-cp-size="99">99%</li>
<li data-cp-size="50">50%</li>
<li data-cp-size="30">30%</li>
<li data-cp-size="90">90%</li>
<li data-cp-size="10">10%</li>
<li data-cp-size="70">70%</li>
<li data-cp-size="30">30%</li>
<li data-cp-size="90">90%</li>
</ul>
</div>At least with inline style you can have the precision you want and are not forced to round your value.
Sooo, yeah it's an interesting exercise but I'm not convinced about the usefulness of that project.