Couple of things to think about -
Bugs have been mentioned a couple of times already but lets think about one common beer spoilage organism Lactobacillus. Most of us heat our mash to over 70oC (personally to nearly 80oC) yet the expended grain will pong a beauty in 24 hours, shows there is plenty of lacto surviving even 80oC. Any gets into your wort and it will be quite happy spoiling your beer from 80oC on down until the beer is ruined. So sealing up your wort hot enough to kill bugs and not unsealing it until you are ready to pitch yeast is a good idea.
Good to remember hat most bacteria reproduce about 6 times faster than yeast, a very small count can get real big real fast!
Oxygen is only good for a wort during that very short time between aerating and pitching, where the yeast will take it up in less than half an hour. Fermenters tend to have much more head space than "cubes" so you will get more O2 uptake by the wort. That assumes you can really seal up a fermenter which I doubt, so as it cools air will be drawn in (hopefully sterile air but don't count on it)
Oxygen harms beer, especially highly hopped beers that are all the rage. It also contributes to staling in other ways to. So all steps taken to minimise O2 exposure after the boil are to the good.
No chill has some real advantages, but spend the small amount of dollars to do it properly. Or invest in the ability to chill your wort down to pitching temperatures quickly. Either way, it will probably wont cost you much more than one lost wort and nothing repays the lost time or the angst induced by tipping what could have been one of your finest.
Mark