Closed captions make an audio-based eLearning more accessible and user-friendly. It makes it easier for people who are hard of hearing to consume the content.
Closed captions also make it possible to engage with a learning experience in loud environments or when audio is not available. Finally, it can help people learn unfamiliar words and follow along with the narration more easily.
That being said, adding closed captions manually to minutes or hours of audio can take a lot of time. To save yourself development time, you can use YouTube's auto-sync feature to automatically generate an .srt file.
You can then import the .srt file into Articulate Storyline and get near-perfect closed captions.