> Do you believe that you could implement the Airbnb interface without any CSS or Javascript?

No, I don't. It has scrollable maps, for example. Those require a Javascript-operated canvas.

What I don't understand is why it needs CSS or Javascript for the rest of the interface. It's just text and photos. An empty css with static html would be enough for that, and convey exactly the same information.

Do you believe the CSS serves absolutely no purpose other than just looking pretty?

I’m also a proponent of simple pages wherever they can be made but we’re not the only audience on the internet. Different people find different UIs effective.

For example: Airbnb (last I looked, anyway) has a little mini carousel in the thumbnail of a listing. I found it mildly useful. I imagine a company the size of Airbnb are tracking if people use that widget so it’s probably earned its place in the interface.

Standing outside the whole thing with no data and saying “none of this is necessary” strikes me as an unhelpful perspective. Neither you nor I actually know.

The web would pretty bland and less usable without CSS. White background and full page width Times New Roman paragraphs, inline images.

User agents could still pick colors! And don't forget about <body bgcolor="#aabbcc">

Does the Airbnb interface need to be implemented at all?

Only if they intend for their business to continue existing.

An interface, sure; but the specific interface they are currently using, to which the previous comment was referring? Of course not.

I mean if I wanted, I could implement any of Airbnb, Twitter, Facebook, HN, Medium in e.g. GTK2 and people could use them with their favorite theme without any issue. Does that count as "without CSS or Javascript", in a non-pedantic sense?