Why it worked
The video uses a popular and attention-grabbing ringtone to hook viewers, then transitions to a direct call to action for a related app, leveraging the initial interest to drive downloads.
Product placement
iPhone ringtone: APPEARS - it is the name of the ringtone playing, but it does not act or change. Removing it would not change what happens in the video.
Marimba Remix Ringtones: ACTS - this is an app that is being promoted, and the video shows its icon, name, rating, and download button. Removing it would change what happens in the video as it is the product being advertised.