Sound is a discovery mechanism, not just a soundtrack
On TikTok and Instagram Reels, audio functions as a searchable, browsable category — tapping a sound takes you to every video using it. That means a trending sound is effectively a distribution channel: your video gets surfaced to people actively browsing that sound's page, in addition to whatever the main algorithm decides to show.
This is different from traditional video, where a soundtrack is purely aesthetic. Here, sound choice is a targeting decision as much as a creative one.
Early adoption beats late adoption
A sound that's already used on millions of videos is oversaturated — your video is one of an enormous pile competing for the same audio-page traffic. A sound that's climbing but not yet flooded gives you a better ratio of visibility to competition. The catch is that 'climbing but not yet flooded' is a narrow, fast-moving window, which is exactly why tracking trending sounds daily (rather than noticing them once they're already everywhere) matters.
Match the sound to the content, not just the trend
A trending sound only helps if it fits naturally with what you're posting. Forcing an unrelated trending audio onto unrelated content tends to produce worse retention — viewers who found you through the sound page bounce quickly if the content doesn't deliver on what that sound usually accompanies. The strongest plays combine a genuinely rising sound with content that would work even without the trend attached.