Some people go to exstrems in cooling the wort very fast as they beleive it makes better beers. It suits me better to split the Brewing in 2 days and hence I practcise the “Easy Chilling” by just let the wort stay in the boiling pot or filter it hot over into the fermet vessel though a strainer! I do try o get the wort down under 80´C as fast as possbile and/or capture the time it takes and re-calculate the IBU in Beersmith2 to account for the isomarization there goes on until you reach 80´C. Especially for hoppy beers with a lot of late additions!
Besides that, then the main reason for a fast cool-down it to lower infection risk. The longer the time the wort is beteween 20-45´C whitout yeast the higher risk there is for an infection to take place. Hence, if the overnight chillling happens in a closed way either in the ferment vessel with airlock on, or in the pot for instance warped in metal-folie+plastic+ruberband (tight), then I am pretty sure the beer can stay this way whitout yeast for rather long time as this would utterl y have the same effect as a pateriuzation.