At least TATL flights are short and they can adapt departures to match the curfews with minimal disruption (aka just delay the departure instead of circling) in contrast with SYD and their 6am curfew which can be a pain for both NA and Asia flights.

It seems like the jet stream has been strong this winter. Flew ATL - BRU in 7:19 a couple of weeks ago which was faster than my JFK - ZRH flight in November (despite being 500 miles longer)