A lot of people are saying that there’s no point to digital contact tracing and to the system that Apple and Google are collaborating to build. If only a small percentage of the population opts-in, what’s the point? That may be true for now! But there are ways it could become a social norm. Or we might decide as a society to accept the tradeoffs necessary if use of the app were to become mandatory, or were to be incentivized in other ways. And at least the technology will exist if and when that happens.