What happens if their private key gets exposed? A third of the internet being suddenly insecure is a really scary prospect. If everything is automated, a lot of

What happens if their private key gets exposed? A third of the internet being suddenly insecure is a really scary prospect. If everything is automated, a lot of smaller sites may not notice until the certificate expires, or even for some time after that. Having more options means less fallout if a CA gets compromised.