It's a good example of knowing your market. It's not universally true that more photos = better for your users.
Google is a good counterexample. Google in its early days was famously not visual - the visual design was incredibly sparse, there were no pictures on the results, there were no pictures on the ads - and that was a huge contrast to most other sites, where you had animated punch-the-monkey graphics scrolling across the screen. The reason for this is that the primary utility for Google (in the early days) was to get you off the site and to your destination as quickly as possible. Anything that drew your attention - other than the result you wanted - was a distraction. Google's made attempts to put pictures on the results pages since - we had plenty of data showing that peoples' attention is instantly drawn to images, and when your department's name is "Search Features" it's awfully tempting to draw attention to the features you're developing - but every such attempt seems to cost Google in brand equity in the long run, and ends up getting reverted eventually.
The key insight for AirBnB was that they are selling an experience, not information. When you're deciding where to book a hotel, you want a visceral sense of how it would feel to be on vacation at that place, and a picture is the best way to achieve that.
The reason for this back then was a slower internet connection. If Google had the bandwidth when they first started they would have inserted images and videos to their search results and ads.
Google is a good counterexample. Google in its early days was famously not visual - the visual design was incredibly sparse, there were no pictures on the results, there were no pictures on the ads - and that was a huge contrast to most other sites, where you had animated punch-the-monkey graphics scrolling across the screen. The reason for this is that the primary utility for Google (in the early days) was to get you off the site and to your destination as quickly as possible. Anything that drew your attention - other than the result you wanted - was a distraction. Google's made attempts to put pictures on the results pages since - we had plenty of data showing that peoples' attention is instantly drawn to images, and when your department's name is "Search Features" it's awfully tempting to draw attention to the features you're developing - but every such attempt seems to cost Google in brand equity in the long run, and ends up getting reverted eventually.
The key insight for AirBnB was that they are selling an experience, not information. When you're deciding where to book a hotel, you want a visceral sense of how it would feel to be on vacation at that place, and a picture is the best way to achieve that.