Here is a thing I see fairly often here on Meta.SE:
The question isn't remotely on-topic and was rightly, and quickly, put on hold. Somebody left a comment (not shown) pointing out what Meta.SE is and steering the OP elsewhere. Sadly, users don't always sit on their questions in real time; sometimes they ask and then come back in a few hours.
If I were to cast that last delete vote, what the OP would see is "my question disappeared", with no further feedback unless the page is still open in a browser tab. The notification for the helpful comment gets removed with the post. I think only experienced SE users would find (a) the right profile tab and (b) the "show recent deleted posts" checkbox. and experienced SE users are not the ones I'm worried about.
How should we respond to these posts? Is there a reasonable amount of time to wait, and after that we should go ahead and delete it? If so, how long is reasonable? Should we just leave these and wait for the Roomba to get them? If so, then when should we be using delete votes on questions? Or should we not concern ourselves with the reactions of new, lost users and delete at will?
In the past I've gone ahead and cast those delete votes, but with the new "welcome wagon" initiative I'm not sure I should be.