For tools which simplify/standarize webpage presentation (e.g., Pocket, Instapaper, Readability) this makes parsing easier.

I'm leaning strongly toward favoring a browser model which just says buggerall to the site's layout and applies a user-specified preference of styling consistently. I'm already pretty much doing this myself via my own CSS mods using Stylebot, and in most cases it makes sites vastly more readable and less distracting.

In particular crap such as Buzzfeed (I call my styling "unbuzzed"): https://plus.google.com/104092656004159577193/posts/G6pzJBLK...

The nightmare of divs makes it hard to find the end div unless someone is disciplined enough to indent the code consistently OR if comments are inserted at the end of divs as in

    <div class="header">
        ...
    </div>  <!-- header-->

Using semantic tags makes it much easier to see the structure.

<header>…</header> header {…}

is slightly shorter than

<div class=header>…</div> .header {…}