Because someone always changes their mind and you get blamed if they cannot change their mind. We are used to a world of Ctrl-Z and customers expect that.

Someone accidentally deletes their company profile as they thought they were deleting the duplicate. They expect to be able to get it back.

Someone wipes out all the config files to get revenge on their employer. That employer is going to get in touch with support to get them back and they expect them back, even if you have to dig through backups and will make support's life difficult if they do not.