If someone steals your domain registration, they can then change the MX records and start receiving your email. In some scenarios, I think that could be a more

If someone steals your domain registration, they can then change the MX records and start receiving your email. In some scenarios, I think that could be a more serious consequence than the website being down or replaced. Same reason that deliberately letting domain registration lapse for a domain that was used widely for email is a scary prospect.