That deletes your hosting account, not your forum account. A forum account is basically a user id for the entire system, so you're not allowed to delete it and staff won't delete it unless there's a good reason you can PM them with. You can have more than one forum account, but being able to use more than one of them means that the forum account you're using won't necessarily be tied to your current hosting account, and that can make support more difficult. Just messing up the account log-in so that you can't accidentally use it is a good way to make sure that doesn't happen.