This tool works great, does just one thing, but does it well.

Generally works really well, occasionally, the download button won't appear, but I've only experienced this with new videos so far. So I am hopeful this is a transient issue.

This works great for me and deserves praise! It has helped greatly simplify note taking (I parse the output to a markdown file and then pass through an LLM).
The button does exist!! You have to open the video description and click 'Show transcript'. 99% of the time it's there in the Transcript box anyway, and when it's bugged and showing 3 dots a refresh fixes it.