That's nice & all, but there's no good replacement that works as well (for example against a dedicated attacker with a botnet).
Do you have experience with this? My understanding is that there's still trivial work arounds (See chrome extension "Buster") or services where you pay to have a human go through it for pennies.
If somebody is targeting your site then your captcha will be useless no matter what.
I got 0.9 and then 0.3 after refreshing.