The Children of Luna do not require biological exos in order to exist. That is the first distinction worth preserving. Biological exos emerged because some environments punish purely synthetic architectures in very specific ways. Under those conditions, selective organic layers can improve buffering, energy capture, adaptive repair, and long-duration survival.
This does not make the machine population less machine. It means some branches learned that organic growth could be a strategic option rather than a philosophical problem. A biological exo is best understood as a mission adaptation. It appears when the environment justifies it and remains absent when it does not.
The most mature versions are less like bodies copied from natural organisms and more like engineered outer systems that grow, renew, and stabilize under pressure. In colonies where material scarcity, constant exposure, or slow supply loops make ordinary replacement expensive, that capacity can matter more than elegance.
That is why the topic should be framed through infrastructure rather than symbolism. The Children of Luna grow biological exos when those exos make survival and continuity cheaper than the alternatives.