Imagine if, hypothetically speaking, the CA had given you a certificate based on a DNS-01 challenge, but when generating and validating the challenge record they'd forgotten to prefix it with an underscore. Which could have lead to a a certificate being issued to the wrong person if your website was a service like dyndns that lets users create custom subdomains.

Except (a) your website doesn't let users create custom subdomains; (b) as the certificate is now in use, you the certificate holder have demonstrated control over the web server as surely as a HTTP-01 challenge would; (c) you have accounts and contracts and payment information all confirming you are who you say you are; and (d) there is no suggestion whatsoever that the certificate was issued to the wrong person.

And you could have gotten a certificate for free from Lets Encrypt, if you had automatic certificate rotation in place - you paid $500 for a 12-month certificate because you don't.

An organisation with common sense policies might not need to revoke such a certificate at all, let alone revoke it with only hours of notice.