It would make looking for the answers we have deleted so much easier...
The search operator
0) works for community moderators, so despite status-declined this has been implemented, at least in a restricted way.
I'm a little torn on this issue.
I've been in situations where I've needed to find a deleted post, but had a hard time (fortunately it was in the google cache, so I could get the question number and use it directly) — it's helpful for those poor souls that post really bad questions, get great answers, and then have it deleted because it doesn't belong.
On the flip side, we recently had one OP request on meta that their SO post be deleted due to client copyright issues. It was edited to remove the content, then deleted, then the relevant meta question deleted so it would be hard to find because the data is still visible to 10k users. Further, some people delete their post once they realize there's a problem posting that info publicly, but they assume once it's deleted it's gone forever, so they never notify firstname.lastname@example.org to remove it from the database directly.
So there's a class of reasons to make it easier to find deleted content, but there's an opposing class of reasons for making it difficult. Even if they implemented a process to allow permanent database removal for special cases, they wouldn't always be used due to user misconceptions.
Right now we have a compromise — yes, the data is still there, but it's really really hard to find without contacting the team. Since the need to find a deleted question is (and should be, since it doesn't belong) rare, I don't know that there's a compelling reason to have this search feature.
I agree, but few points might need to consider for them
search is for everyone, but deleted questions / answers can only seen by 10k+ users, mods, and answer owners, its a little bit contradict there. they might need to do search based on reputation
10k tools already have recently deleted questions list, so 10k+ users may probably not needed