It emphasizes the reliability of the MacBook Air by showing that some of them have scuffs and scrapes. It’s rare in that it shows Apple products in a non-retail-box condition. The only recent personalization example I can find is iPhones in cases, which are shown in its ‘Powerful’ ads — but those don’t show any actual ‘damage’. The way Apple products look after customization and ‘real world’ use isn’t often represented in Apple ads. As Jeff Carlson points out, these are likely someone’s real machines.
The first thing I thought of with this ad was that it was a less-’90s-cliché, skewing-younger, more playful (and literal) version of the “What’s on Your PowerBook?” ad campaign. It’s showing how a generic machine can mean so many different things to so many different people.