We've decided to develop our own app because by having a centralised dataset we can more intelligently respond to outbreaks within the population. If it goes to plan, it would keep everyone safer and allow us to ease the lockdown more quickly.
The Google and Apple model is de-centralised, so you're not handing over any location data, but there's no opportunity for the epidemiologists to try and figure out the best of controlling the outbreak.
Quite why people are happy to hand over all of their location data, web browsing data and more to multi-national corporations, but suddenly get their tin-foil hats on when it's going to some academics who are trying to tackle the virus is beyond me, but there you go.
There are some technical challenges to overcome, which I'm not convinced we'll be able to get around, but we'll have to wait and see how the trial goes on the Isle of Wight.