Military without GPS would be blocked. Try navigating in jungle environments where everything is green and looks the same. I've experienced both with GPS and without, that was one heck of a game changer.
[1] https://qz.com/1106064/the-entire-global-financial-system-de...
ATMs may be designed to use super precise timstamps, but they don't need to be. At all.
The interesting timing constraints are between stock exchanges... but in those situations the speed of light is a bigger factor than clock drift, even if you're just using NTP, and you can't avoid speed of light delays/desyncs.
For stock exchanges you are absolutely correct. I remember many years ago paying so much extra for the fastest internet access and sub-second delay access to our local stock exchange. Even so it was still slower (lag) when compared to those with offices placed very close to the stock exchange building/infrastruture at that time.