It's also very effective at excluding people like me. Even when logged in to a Google account with a very benign history (mostly used to watch youtube) with years (>4) of regular activity, Google won't[1] even attempt reCAPTCHA (any version) because they think my browser isn't one of the handful of specific browser versions they support[2]. The actual browser version is fine, it's configured similar to the Tor browser minimize data leaks and browser fingerprinting. So I cannot use any site with reCAPTCHA not because of any technical limitation; unless I "upgrade"[1] to a configuration that leaks a lot more data.

[1] https://imgur.com/9wT9yZ2 [ignore font/layout issues in that image - my usercss and fontconfig/freetype font rendering settings are very unusual, complex, and often very disruptive]

[2] https://support.google.com/recaptcha/?hl=en#6223828 "We support the two most recent major versions of the following: [Desktop: Chrome, Firefox, Safari, Edge]"