It's much more than a bit flip - that's just the input. The output side is where tooling like this becomes useful, i.e., getting analytics on each variant. That

It's much more than a bit flip - that's just the input. The output side is where tooling like this becomes useful, i.e., getting analytics on each variant. That's what lets you run A-B tests to optimise conversion, ensure a new feature isn't going to cause stabilty problems, etc. And then there's the need for interfaces to allow changes on a live system, and giving certain abilities to non-technical users who want to change settings on a simple web dashboard. If an external service goes down, the system should be able to degrade gracefully. I haven't used an external service, but I'd hope the SDK allows for a simple fallback strategy for each flag, such as random assignment or fixing to a particular value. Data collection should still resume once the external service is back up.