I'm building the subtitle tool I've been wishing existed

If you're learning a language through shows/anime, you know the subtitle problem:
Subs don't match the dub. They're usually way simpler than what's actually being said - some are decent, most aren't.
Looking up a word kills your flow. Retype it into a translator (slow) or screenshot + AI (slower). Either way, you've lost the scene.
So I'm building a fix. Not a bloated app - a lightweight Chrome extension.

How it works: open your browser, hit play on any video. Subtitles generate automatically. See a word you don't know? Click it - a popup shows the full sentence with that word highlighted and translated, right in context.
No account. No setup. Just works.

Would you use this? What's missing?