I suppose it could be argued that compacting (taking multiple sparse archives and re-compressing them into a single non-sparse one) is different than deleting a 100% unused archive.
So it’s possible the straight-up delete of an encrypted file even might actually work as discussed - I think testing or a question to @kenkendk might be needed to answer that one.
The actual benefit of such functionality would vary greatly be user. For example, if you have a bunch of video files that never change and decide to delete one then removal all (or most) of the related archive files should happen pretty quickly.
However, if you’re working on writing a book and it’s contents change daily, then the likelihood of older version archives being 100% unused (thus deletable) is pretty low unless the original contents of your book have changed enough that EVERY original block is not longer used.
Basically, I’m worried that such a setting would cause archives very infrequently be deleted (frequency doing DOWN as size goes up) and the resulting “flagged for deletion” records sitting in the database long term could slow down run times.