there is a delete button...? and typically, download managers download a file, then maybe optionally extract it, but always keep the actual file you asked them to download. maybe it mistakes a non-archive file for an archive and extracts it when you didnt want it to, now the real file is impossible to download because its gone right after downloading. or maybe you delete some stuff from the extracted files but mistakenly delete one you wanted to keep, you still have the archive to get it out without redownloading everything. so yeah, no autodelete, it deletes when you tell it to.
anyway, i implemented donor ddl in subfolders in latest beta.