I have worked on and around systems with an order of magnitude more data and a single node failing did not matter. We weren't using btrfs anyway (for data drives) and it definitely was not cheap. But storage never is.

But again, most systems are not like that. Kubernetes cluster nodes? Reimage at will. Compute nodes for vms backed by SAN? Reimage at will. Btrfs can actually make that reimage faster and it's pretty reliable on a single flash drive so why not?