A separate concern I have is that Web sites running ReCaptcha often require leaking privacy-invasive information to Google, in the course of using the site.
Not only does Google presumably usually know exactly who you are when you visit that site, but even if you normally block other Google hidden Web trackers, you can't block the ReCaptcha tracker, so in some cases Google can have a very good idea of what you do on the site.
So, while this browser extension might relieve some of the visible annoyance, it doesn't relieve the more insidious problem.
Not only does Google presumably usually know exactly who you are when you visit that site, but even if you normally block other Google hidden Web trackers, you can't block the ReCaptcha tracker, so in some cases Google can have a very good idea of what you do on the site.
So, while this browser extension might relieve some of the visible annoyance, it doesn't relieve the more insidious problem.