One situation where a delete feature could be helpful is when you inadventently make a duplicate post. This can happen when you click on Submit but nothing seems to happen for a long time and then you click on it again, or do a refresh or some such. Something like that happened to me yesterday and I wasn't able to delete the duplicate post.
This seems like a non-problem. In the case of your node, it was reaped 31 minutes after it was created. Perhaps if you had yourself considered it for deletion it would have been even faster. Yes, the current process involves several people and a short time delay; IMO those are good things.