CSS is providing newer and more complex methods of laying out your pages. Given the multiple form factors a responsive site has to support, it makes sense that developers want easy ways to structure the layouts that aren’t all floats, clears and position: absolutes.
Regardless of how you want your layout to appear in a browser, you must keep in mind that a clear HTML structure is [start of stricken text] important to search engines[end stricken text] . Sorry, while the bit about search engines is true, it’s not really what I consider important, but it is more likely to get some people to pay attention.
I still think it’s pretty messed up that, for the purpose of getting the topic of equal access for all on the web some play, we have to refer to the benefits for search engine optimization, (most of which are myths), because that’s the only way most people are going to pay attention. It’s either that, or try scaring people by reminding that eventually, they won’t be fully abled. I get it, I’m not going to stop doing it, but it’s still one of the less-desirable, less-lovable parts of accessibility for me.