the only time it is ok is when it is backups that are superseded by new backups, or a trash storage where i put things manually, and even there i prefer to empty the trash manually too.

but this is just how i am used to working. i realize that i accept messages in irc disappearing if i don't log them too (but then i set up logs for quite a number of channels that matter to me), and i could accept this service for certain use cases like for mailing lists which are usually archived elsewhere anyways.

but i could not use it for emails from family, friends or customers who might send me things that i want to keep.

furthermore, if you consider encrypted email you can't even tell what is an attachment and what is the body. removing the attachment would also affect unencrypted, but signed emails.