Re: in large part because DNS providers don't see much of an upside to offering it
"Without a CAA record I can go to a CA and get a valid certificate for theregister.co.uk and then perform a MITM attack."
No you can't. If you can then go ahead and do it. Is it possible? Yes, but there would have to be other security breakdowns with the trusted root authority or elsewhere (hacked into the register email system) to be able to do it.