On Thu, 17 Sep 2020 07:12:14 +1000, wrote:

Yes, that not as good as with those with
symptoms, but it¢s a lot better than nothing.

Pinning all your hopes on a talisman is _not_ "a lot better than nothing".

o What Ever Happened to Digital Contact Tracing?
https://www.lawfareblog.com/what-ever-happened-digital-contact-tracing

"It will be an uphill battle even to hit the 10 percent mark in America"

"Under a range of assumptions, the percentage of the population needed
to be enrolled in automated contact tracing for outbreak control (Re1)
was estimated (eg, 40%-60% uptake required for Re1, assuming a 30% mean
transmission probability per contact event, if 75%-95% actively confirm
when they get infected"