> The only time exponential backoff is useful is if the failure is due to a rate limit and you specifically need a mechanism to reduce the rate at which you are attempting to use it.

That's what you should be using exponential backoff for. In actuality, the new latency introduced by the backoff should be maintained for some time even after a successful request has been received, and gradually over time the interval reduced.

> I much prefer setting a fixed time period to wait between retries (would you call that linear backoff? no backoff?)

I've heard it referred to as truncated exponential backoff.