I just deleted my question that got closed by an admin and added a new one.
Why delete an old question? There could be people, who are interested in the answer of that question.
Unless there is an "asking restriction" (=you cannot post new questions without deleting the answered ones), there is no real advantage of deleting old questions. But why would there be such restriction? It is pointless/meaningless.
The question I deleted was no longer able to be voted on (which didn't help towards the goal of moving on to the next phase), and I couldn't ask a new question without deleting, it as each person is limited to 5 questions each.
EDITED TO ADD: And the message I got from the admin who closed my question was: