I disagree somewhat. I think that is hindsight bias to relate the website's 2008 designs to cause&effect of VC decisions.
The April 2015 website designs looks "prettier" but as far as communicating to unknowing customers (and uninformed VCs) what Airbnb actually does, the "uglier" 2008 designs are actually better.
Notice that the 2008 designs have icons/pictures of an actual "bed" and a "breakfast". It's concrete visual communication. But the 2015 photos instead, show "people" in what I call "aspirational lifestyle" poses. It's abstract visual communication. (And I just took another quick look at airbnb.com today July 13 2015 and now the home page shows photos of "destinations" overlayed with city names in prominent white font. So now the page design taps into the romanticisms of the Condé Nast Traveler. The visual abstractions continue.)
I think it's fascinating the lifecycle of companies's visual style that transition from The Concrete --> The Abstract. The visuals including marketing, advertisements, and home webpage designs.
The concrete approach has to show the actual product. The abstract does not.
At this point, I think Airbnb can get away with abstract visuals because they are well-known enough now to not have to waste landing page pixels on an actual "bed" or "eggs & toast". That's what 7 years of penetrating the public consciousness allows you to do. These days, I would guess that the majority of visitors already know (by way of friends & family) what Airbnb does before they visit airbnb.com.
Therefore, if the company is a startup nobody knows, they must use concrete visuals. If a company is established and successful, they have the luxury of being abstract. I don't think tomorrow's YC2016 unknown company should base their website's information design based on airbnb's 2015 website. Instead, look at their 2008 designs even though they are uglier.
Other examples of companies doing abstract visuals:
Nike's "Just Do It" commercials often do not highlight any shoes in obvious ways and instead show sweaty people running or playing.[1] (If one didn't know Nike was a shoe and sports apparel company, one might think that commercial was about karate lessons.)
Viagra commercial don't show the actual pills but instead shows older couples holding hands walking the beach or a guy sailing a boat.[2] This is unlike many Tylenol pills commercials showing the actual pills.[3]
Even in the tech world has examples. Anyone remember the old IBM OS/2 Warp commercials in 1990s? The entire commercial was showing people's faces looking at a computer screen (presumably of OS/2). The camera didn't show what they were looking at -- therefore you saw no GUI demostrations. The camera also didn't show the software box. It was just a bunch of reaction shots of people's faces showing astonishment ("wow!", "cool!", etc). [4]
The abstract commmercials from Nike & IBM are not suitable for convincing investors who don't understand athletic shoes or operating system software. Likewise, the 2015 versions of airbnb.com showing abstract lifestyle photos are not useful for potential investors either.
[1]https://www.youtube.com/watch?v=Pp5dZZBKTXQ
[2]https://www.youtube.com/watch?v=y1ZqQ55T25c