Yes, the finding is definitely interesting because it suggests that we could make this available very broadly (i.e., anyone with an appropriate Apple Watch) wit

Yes, the finding is definitely interesting because it suggests that we could make this available very broadly (i.e., anyone with an appropriate Apple Watch) without needing to ship a bunch of hardware. But the limitations are worth noting: you may already have infected people by the time this detects your illness. That isn't true for lateral flow tests, making the latter more useful as a preventative testing tool (again, in the absence of access differences). However, I don't understand what you're trying to say with this claim: > Yes, to make these same predictions you'd have to do some statistics as described in the paper, but no special app is required. "Do some statistics" is approximately as impossible as "order lateral flow test reagents" to the general public -- a consumable version of either the process described in this paper, or the lateral flow kits mentioned earlier, needs to be produced by someone skilled here, in order for this to be useful to the general public.