Read-only wearable devices vs. read-write systems: How insulin pumps and more rewrite body signals

A read-write device asks a different question than a tracker does. What can we do about it right now?

What are read-only wearable devices, and how do they differ from read-write systems?

The move from read-only tracking to closed-loop intervention is not a marketing tweak. It changes what a wearable is for.