Says Brian Monaco, president and global chief marketing officer at Sony Music Publishing: “It’s called ‘trailerizing’ a song. That means changing every aspect of the song but leaving the lyrics. People know the lyrics. The goal is to catch people’s attention. Maybe they’re not paying as much attention to the trailer, and they start to hear the chorus of the song, and they go, ‘Wait, I know this song.’ They start paying attention, and now they’re watching the trailer.” 

Source: Trailers Use Slower and Moodier New Versions of Classic Songs to Lure Viewers