Having an app per country was unnecessary to begin with. All that Google and Apple had to do is supply the UI and accept government requests to enable the system in their country.
Apple and Google’s thing was late to the party too, both Singapore and Australia had published their apps before the in built OS exposure notification because a thing (and I’d ballpark over 90% of Android phones haven’t got OS upgrades available that let them use the Google one anyway, none of my Android devices have it, being stuck with no manufacturer support or locked down by carriers).
So Australia and Singapore pushed on with their non OS native versions of the apps, even though the Bluetooth implementation on iOS made it very unreliable if the app wasn’t running and in the foreground. (The Android version’s Bluetooth is more reliable, if just chews through battery at a very quick pace...)
The end result is almost no useful data has come out of it here: https://www.theguardian.com/australia-news/2020/dec/15/covid...
Just 20 “close contacts” identified, and the government stalling on freedom of information requests to find out if any active cases were identified from those.
The article seems to blame the lack of uptake.
Singapore doesn't have this problem, having dangled further relaxation of lockdown restrictions if more of its residents downloaded the app: https://www.straitstimes.com/singapore/phase-3-unlikely-by-e...