If all things considered within cycle time - as you correctly say - indicate a developer's forecast for delivery timelines, and one developer over a large enough period of time working on the same codebase has half the cycle time as another, does that really tell you nothing?
Assume you're in a team where work is distributed uniformly and not some of this faster person only picking up small items.
Assume you're in a team where work is distributed uniformly and not some of this faster person only picking up small items.