China also shows that these apps (which combine track and trace, with status) are very useful to re-open the economy after lockdowns in a way that helps contain further outbreaks.

Of course, saying "it seems to work in China" is the surest way to having a course of action shot down as unacceptable whatever its actual merits...

Part of the problem is that the mainstream media - including the BBC - seem to have mislead people about how well contact tracing worked in places like South Korea. For example, they ran an article a few months back about how it was so effective that South Korea could reopen their pubs and nightclubs. In reality, they'd tried doing that multiple times and every time, cases had started going up enough that they had to close them again - but you wouldn't know that from the article. Nor would you have known that the same thing happened that time; the BBC kept on completely ignoring the rise in cases there even as they reported less important stories from South Korea.

Covid still isn't in control in South Korea. (Singapore maybe, but that relied on their society being structured in a way that wouldn't be politically acceptable elsewhere. If you take a look at the infection rate in their worker dorms, and realise those people would be living amongst the rest of the community in equally crowded housing and shopping at the same stores in Western countries - just like they were in Singapore until they were forced into dorms so actual citizens didn't have to look at them - and that those infections weren't even counted as "community cases" there...)