[arter45]

End users do all kinds of stuff, but as a developer you're supposed to gather (even elicit, at times!) requirements from users or stakeholders who act as proxies for actual users.

Store something so you can read it in a year or even after a blackout is a user requirement, which leads to persistence.

And if this is a user requirement, deleting ("un-storing") is a user requirement too.

"I want to delete something but I also want to recover it" is another requirement.

Of course,you could also have regulatory requirements pointing to hard-deleting or not hard-deleting anything, but this also holds for a lot of other issues (think UX - accessibility can be constrained by regulations, but you also want users to somehow have a general idea of the user experience).