> I wasn't a big fan of the Covid tracing app in the beginning, but in retrospect the concept of that app seems miles ahead of the current situation with the Luca app.

I think the concept behind is really solid and a great example for what is possible w/o invading privacy. The only problem is that development got very very slow after the initial release and a lot of potential was wasted. E.g. adding some kind of check in feature was already discussed mid last year but it took them until now to pick that idea up.