Genuine question: why wouldn’t they have been doing this already? It feels like obvious low-hanging fruit on a critical path, so I presume there’s something more to it than I’m imagining.

Speculation, no insider info: Its one more thing that needs to be sent out to all their proxies, and could be a reason for meaningfully different metrics whenever the (non-time-critical) regular updates fail. The more configuration/state each proxy receives and processes, the more difficult it will be to determine what is wrong when one exhibits abnormal behavior. At least one of the serious outages was even directly attributed to having accidentally exceeded some hard limit (very hard actually, a rust panic) in how much data could be distributed through one particular such channel, see https://blog.cloudflare.com/18-november-2025-outage/