It's a massive time-saver if you don't have to write out text, get it into your video project, align it correctly, and make corrections. It's now automatic in Premiere Pro, and it's something that puts Adobe ahead of Final Cut and Da Vinci Resolve.
If you've recorded an interview with someone and you want to add value to your deliverable, adding captions to your social video content is a great way to do so. The caption text is also added to the timeline in a new track aligned with the voices. Where I see this as very valuable is if you want to add some animated graphics to your video, where the spoken word is enhanced with the text graphics. Now, it's much easier to get the text into your video, and adding effects is much easier too.
The voices can also be allocated to whomever you're shooting, and the AI should pick up on this and automatically add each voice to its rightful owner. It's also not only catering to English-speaking people. It's got 11 other languages you can work with. Be sure to check it out.