I just saw a new comment added here today (I can't see it now - not sure where it went) - which claimed that the Post Expirator's "delete" option deletes the post permanently, rather than moving it to the Trash, and that this is because the plugin calls wp_delete_post() rather than wp_trash_post().
However I don't believe this is correct. Firstly, I've been using Post Expirator with the "delete" option myself, and all of the deleted posts are in my Trash, they're not deleted permanently. Secondly, the wp_delete_post() function actually does send posts to the Trash by default, as long as its $force_delete parameter is set to 'false', which it is by default. The Function Reference page at https://codex.wordpress.org/Function_Reference/wp_delete_post explains, "wp_delete_post() automatically reverts to wp_trash_post() if $force_delete is false".
Therefore I believe this feature request is not needed, because the plugin already does exactly this. :)
Isn't that what happens when you set it to expire with "delete"?
What do you mean by "the archive for that category"? I don't believe WordPress categories have any kind of "archive" feature. A post simply belongs to a category, there is no separate "archive" part of a category.
I'm not a developer of this plugin, but I believe this plugin merely automates changing certain aspects of a post's status that you can already change yourself manually - eg. deleting it, changing its category, changing its status to Draft, or changing its visibility to Private. These are all things that you can do yourself manually - this plugin just does one of those things automatically for you. My point is that the plugin can't do something which WordPress itself doesn't already do. :)